Initial commit
These used to be part of my dwm fork repository.
This commit is contained in:
445
brightness.c
Normal file
445
brightness.c
Normal file
@@ -0,0 +1,445 @@
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/*
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* brightness.c: set display brightness via DDC/CI - Linux only
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*
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* Copyright (c) 2015, Přemysl Janouch <p.janouch@gmail.com>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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// Sources: ddcciv1r1.pdf, i2c-dev.c in Linux, ddccontrol source code,
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// http://www.boichat.ch/nicolas/ddcci/specs.html was also helpful
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// This makes openat() available even though I set _POSIX_C_SOURCE and
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// _XOPEN_SOURCE to a version of POSIX older than 2008
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#define _GNU_SOURCE
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// Undo some dwm Makefile damage and import my everything-library
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#include "config.h"
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#undef PROGRAM_NAME
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#define PROGRAM_NAME "brightness"
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#include "liberty/liberty.c"
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#include <sys/ioctl.h>
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#include <dirent.h>
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#include <linux/i2c.h>
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#include <linux/i2c-dev.h>
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static void
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log_message_custom (void *user_data, const char *quote, const char *fmt,
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va_list ap)
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{
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(void) user_data;
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FILE *stream = stdout;
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fprintf (stream, PROGRAM_NAME ": ");
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fputs (quote, stream);
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vfprintf (stream, fmt, ap);
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fputs ("\n", stream);
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}
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#define FAIL(...) \
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BLOCK_START \
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error_set (e, __VA_ARGS__); \
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return false; \
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BLOCK_END
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static void
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wait_ms (long ms)
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{
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struct timespec ts = { 0, ms * 1000 * 1000 };
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nanosleep (&ts, NULL);
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}
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static bool
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xstrtol (const char *s, long *out)
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{
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char *end;
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errno = 0;
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*out = strtol (s, &end, 10);
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return errno == 0 && !*end && end != s;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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#define DDC_LENGTH_XOR 0x80
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enum
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{
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DDC_ADDRESS_HOST = 0x50, ///< Bus master's base address
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DDC_ADDRESS_DISPLAY = 0x6E ///< The display's base address
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};
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enum { I2C_WRITE, I2C_READ };
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enum
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{
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DDC_GET_VCP_FEATURE = 0x01, ///< Request info about a feature
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DDC_GET_VCP_FEATURE_REPLY = 0x02, ///< Feature info response
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DDC_SET_VCP_FEATURE = 0x03 ///< Set or activate a feature
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};
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enum
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{
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VCP_BRIGHTNESS = 0x10, ///< Standard VCP opcode for brightness
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VCP_CONTRAST = 0x12 ///< Standard VCP opcode for contrast
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};
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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check_edid (int fd, struct error **e)
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{
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uint8_t edid_req[] = { 0x00 };
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uint8_t buf[8] = "";
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struct i2c_msg bufs[] =
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{
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{ .addr = 0x50, .flags = 0,
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.len = 1, .buf = edid_req },
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{ .addr = 0x50, .flags = I2C_M_RD,
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.len = sizeof buf, .buf = buf },
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};
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struct i2c_rdwr_ioctl_data data;
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data.msgs = bufs;
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data.nmsgs = 2;
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if (ioctl (fd, I2C_RDWR, &data) < 0)
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FAIL ("%s: %s", "ioctl", strerror (errno));
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if (memcmp ("\x00\xFF\xFF\xFF\xFF\xFF\xFF\x00", buf, sizeof buf))
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FAIL ("invalid EDID");
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return true;
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}
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static bool
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is_a_display (int fd, struct error **e)
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{
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struct stat st;
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if (fstat (fd, &st) < 0)
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FAIL ("%s: %s", "fstat", strerror (errno));
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unsigned long funcs;
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if (!(st.st_mode & S_IFCHR)
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|| ioctl (fd, I2C_FUNCS, &funcs) < 0
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|| !(funcs & I2C_FUNC_I2C))
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FAIL ("not an I2C device");
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return check_edid (fd, e);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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ddc_send (int fd, unsigned command, void *args, size_t args_len,
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struct error **e)
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{
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struct str buf;
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str_init (&buf);
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str_pack_u8 (&buf, DDC_ADDRESS_HOST | I2C_READ);
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str_pack_u8 (&buf, DDC_LENGTH_XOR | (args_len + 1));
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str_pack_u8 (&buf, command);
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str_append_data (&buf, args, args_len);
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unsigned xor = DDC_ADDRESS_DISPLAY;
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for (size_t i = 0; i < buf.len; i++)
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xor ^= buf.str[i];
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str_pack_u8 (&buf, xor);
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struct i2c_msg msg =
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{
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// The driver unshifts it back
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.addr = DDC_ADDRESS_DISPLAY >> 1, .flags = 0,
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.len = buf.len, .buf = (uint8_t *) buf.str,
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};
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struct i2c_rdwr_ioctl_data data;
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data.msgs = &msg;
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data.nmsgs = 1;
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bool failed = ioctl (fd, I2C_RDWR, &data) < 0;
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str_free (&buf);
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if (failed)
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FAIL ("%s: %s", "ioctl", strerror (errno));
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return true;
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}
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static bool
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ddc_read (int fd, unsigned *command, void *out_buf, size_t *n_read,
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struct error **e)
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{
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uint8_t buf[128] = "";
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struct i2c_msg msg =
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{
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// The driver unshifts it back
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.addr = DDC_ADDRESS_DISPLAY >> 1, .flags = I2C_M_RD,
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.len = sizeof buf, .buf = buf,
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};
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struct i2c_rdwr_ioctl_data data;
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data.msgs = &msg;
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data.nmsgs = 1;
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if (ioctl (fd, I2C_RDWR, &data) < 0)
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FAIL ("%s: %s", "ioctl", strerror (errno));
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struct msg_unpacker unpacker;
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msg_unpacker_init (&unpacker, buf, sizeof buf);
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uint8_t sender, length, cmd;
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(void) msg_unpacker_u8 (&unpacker, &sender);
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(void) msg_unpacker_u8 (&unpacker, &length);
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(void) msg_unpacker_u8 (&unpacker, &cmd);
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if (sender != (DDC_ADDRESS_DISPLAY | I2C_WRITE) || !(length & 0x80))
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FAIL ("invalid response");
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if (!(length ^= 0x80))
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FAIL ("NULL response");
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// TODO: also check the checksum
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*command = cmd;
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memcpy (out_buf, unpacker.data + unpacker.offset, (*n_read = length - 1));
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return true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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set_brightness (int fd, long diff, struct error **e)
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{
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uint8_t get_req[] = { VCP_BRIGHTNESS };
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if (!ddc_send (fd, DDC_GET_VCP_FEATURE, get_req, sizeof get_req, e))
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return false;
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wait_ms (40);
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unsigned command = 0;
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uint8_t buf[128] = "";
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size_t len = 0;
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if (!ddc_read (fd, &command, buf, &len, e))
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return false;
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if (command != DDC_GET_VCP_FEATURE_REPLY || len != 7)
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FAIL ("invalid response");
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struct msg_unpacker unpacker;
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msg_unpacker_init (&unpacker, buf, len);
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uint8_t result; msg_unpacker_u8 (&unpacker, &result);
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uint8_t vcp_opcode; msg_unpacker_u8 (&unpacker, &vcp_opcode);
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uint8_t type; msg_unpacker_u8 (&unpacker, &type);
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int16_t max; msg_unpacker_i16 (&unpacker, &max);
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int16_t cur; msg_unpacker_i16 (&unpacker, &cur);
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if (result == 0x01)
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FAIL ("error reported by monitor");
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if (result != 0x00
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|| vcp_opcode != VCP_BRIGHTNESS)
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FAIL ("invalid response");
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// These are unsigned but usually just one byte long
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if (max < 0 || cur < 0)
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FAIL ("capability range overflow");
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int16_t req = (cur * 100 + diff * max + 50) / 100;
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if (req > max) req = max;
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if (req < 0) req = 0;
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uint8_t set_req[] = { VCP_BRIGHTNESS, req >> 8, req };
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if (!ddc_send (fd, DDC_SET_VCP_FEATURE, set_req, sizeof set_req, e))
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return false;
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wait_ms (50);
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printf ("brightness set to %.2f%%\n", 100. * req / max);
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return true;
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}
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static void
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i2c (long diff)
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{
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DIR *dev = opendir ("/dev");
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if (!dev)
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{
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print_error ("cannot access %s: %s: %s",
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"/dev", "opendir", strerror (errno));
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return;
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}
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struct dirent *entry;
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while ((entry = readdir (dev)))
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{
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if (strncmp (entry->d_name, "i2c-", 4))
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continue;
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printf ("Trying %s... ", entry->d_name);
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int fd = openat (dirfd (dev), entry->d_name, O_RDONLY);
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if (fd < 0)
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{
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print_error ("%s: %s", "openat", strerror (errno));
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continue;
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}
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struct error *e = NULL;
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if (!is_a_display (fd, &e)
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|| !set_brightness (fd, diff, &e))
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{
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printf ("%s\n", e->message);
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error_free (e);
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}
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close (fd);
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}
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closedir (dev);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static long
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read_value (int dir, const char *filename, struct error **e)
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{
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int fd = openat (dir, filename, O_RDONLY);
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if (fd < 0)
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{
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error_set (e, "%s: %s: %s", filename, "openat", strerror (errno));
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return -1;
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}
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FILE *fp = fdopen (fd, "r");
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if (!fp)
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{
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error_set (e, "%s: %s: %s", filename, "fdopen", strerror (errno));
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close (fd);
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return -1;
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}
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struct str s;
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str_init (&s);
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long value;
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if (!read_line (fp, &s)
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|| !xstrtol (s.str, &value))
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{
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value = -1;
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error_set (e, "%s: %s", filename, "failed reading an integer value");
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}
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str_free (&s);
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fclose (fp);
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return value;
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}
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static bool
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set_backlight (int dir, long diff, struct error **e)
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{
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long cur, max;
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struct error *error = NULL;
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if ((cur = read_value (dir, "brightness", &error), error)
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|| (max = read_value (dir, "max_brightness", &error), error))
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{
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error_propagate (e, error);
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return false;
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}
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if (cur < 0 || max < 0)
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{
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error_set (e, "invalid range or current value");
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return false;
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}
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long req = (cur * 100 + diff * max + 50) / 100;
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if (req > max) req = max;
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if (req < 0) req = 0;
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int fd = openat (dir, "brightness", O_WRONLY);
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if (fd < 0)
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{
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error_set (e, "%s: %s: %s", "brightness", "openat", strerror (errno));
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return false;
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}
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struct str s;
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str_init (&s);
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str_append_printf (&s, "%ld", req);
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bool result = write (fd, s.str, s.len) == s.len;
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str_free (&s);
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if (!result)
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error_set (e, "%s: %s: %s", "brightness", "write", strerror (errno));
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close (fd);
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printf ("brightness set to %.2f%%\n", 100. * req / max);
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return result;
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}
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static void
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backlight (long diff)
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{
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DIR *backlight = opendir ("/sys/class/backlight");
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if (!backlight)
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{
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print_error ("cannot access %s: %s: %s",
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"/sys/class/backlight", "opendir", strerror (errno));
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return;
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}
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struct dirent *entry;
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while ((entry = readdir (backlight)))
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{
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const char *device_name = entry->d_name;
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if (device_name[0] == '.')
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continue;
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printf ("Trying %s... ", entry->d_name);
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int dir = openat (dirfd (backlight), entry->d_name, O_RDONLY);
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if (dir < 0)
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{
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print_error ("%s: %s", "openat", strerror (errno));
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continue;
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}
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struct error *e = NULL;
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if (!set_backlight (dir, diff, &e))
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{
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printf ("%s\n", e->message);
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error_free (e);
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}
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close (dir);
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}
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closedir (backlight);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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int
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main (int argc, char *argv[])
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{
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g_log_message_real = log_message_custom;
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long diff = 0;
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if (argc > 1 && !xstrtol (argv[1], &diff))
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{
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printf ("Usage: %s <percentage diff>\n", argv[0]);
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exit (EXIT_FAILURE);
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}
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i2c (diff);
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backlight (diff);
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return 0;
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}
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Block a user