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Merge pull request #24250 from yuwata/backlight-multiple-graphics-cards

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backlight: support multiple graphics cards system
This commit is contained in:
Yu Watanabe 2022-08-17 21:58:59 +09:00 committed by GitHub
parent 86b4e141a5 e0504dd011
commit 190169e591
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 118 additions and 34 deletions
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152
src/backlight/backlight.c
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@ -21,6 +21,8 @@
#include "terminal-util.h"
#include "util.h"
#define PCI_CLASS_GRAPHICS_CARD 0x30000
static int help(void) {
_cleanup_free_ char *link = NULL;
int r;
@ -44,6 +46,47 @@ static int help(void) {
return 0;
}
static int has_multiple_graphics_cards(void) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
sd_device *dev;
bool found = false;
int r;
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_subsystem(e, "pci", /* match = */ true);
if (r < 0)
return r;
/* class is an unsigned number, let's validate the value later. */
r = sd_device_enumerator_add_match_sysattr(e, "class", NULL, /* match = */ true);
if (r < 0)
return r;
FOREACH_DEVICE(e, dev) {
const char *s;
unsigned long c;
if (sd_device_get_sysattr_value(dev, "class", &s) < 0)
continue;
if (safe_atolu(s, &c) < 0)
continue;
if (c != PCI_CLASS_GRAPHICS_CARD)
continue;
if (found)
return true; /* This is the second device. */
found = true; /* Found the first device. */
}
return false;
}
static int find_pci_or_platform_parent(sd_device *device, sd_device **ret) {
const char *subsystem, *sysname, *value;
sd_device *parent;
@ -72,7 +115,7 @@ static int find_pci_or_platform_parent(sd_device *device, sd_device **ret) {
return -ENODATA;
c += strspn(c, DIGITS);
if (*c == '-' && !STARTSWITH_SET(c, "-LVDS-", "-Embedded DisplayPort-"))
if (*c == '-' && !STARTSWITH_SET(c, "-LVDS-", "-Embedded DisplayPort-", "-eDP-"))
/* A connector DRM device, let's ignore all but LVDS and eDP! */
return -EOPNOTSUPP;
@ -86,7 +129,7 @@ static int find_pci_or_platform_parent(sd_device *device, sd_device **ret) {
value, subsystem, sysname);
/* Graphics card */
if (class == 0x30000) {
if (class == PCI_CLASS_GRAPHICS_CARD) {
*ret = parent;
return 0;
}
@ -130,7 +173,7 @@ static int same_device(sd_device *a, sd_device *b) {
static int validate_device(sd_device *device) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *enumerate = NULL;
const char *v, *subsystem;
const char *v, *sysname, *subsystem;
sd_device *parent, *other;
int r;
@ -145,80 +188,121 @@ static int validate_device(sd_device *device) {
* device to userspace. However, we still need to make sure that we use "raw" only if no
* "firmware" or "platform" device for the same device exists. */
r = sd_device_get_sysname(device, &sysname);
if (r < 0)
return log_device_debug_errno(device, r, "Failed to get sysname: %m");
r = sd_device_get_subsystem(device, &subsystem);
if (r < 0)
return r;
return log_device_debug_errno(device, r, "Failed to get subsystem: %m");
if (!streq(subsystem, "backlight"))
return true;
r = sd_device_get_sysattr_value(device, "type", &v);
if (r < 0)
return r;
return log_device_debug_errno(device, r, "Failed to read 'type' sysattr: %m");
if (!streq(v, "raw"))
return true;
r = find_pci_or_platform_parent(device, &parent);
if (r < 0)
return r;
return log_device_debug_errno(device, r, "Failed to find PCI or platform parent: %m");
r = sd_device_get_subsystem(parent, &subsystem);
if (r < 0)
return r;
return log_device_debug_errno(parent, r, "Failed to get subsystem: %m");
if (DEBUG_LOGGING) {
const char *s = NULL;
(void) sd_device_get_syspath(parent, &s);
log_device_debug(device, "Found %s parent device: %s", subsystem, strna(s));
}
r = sd_device_enumerator_new(&enumerate);
if (r < 0)
return r;
return log_oom_debug();
r = sd_device_enumerator_allow_uninitialized(enumerate);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to allow uninitialized devices: %m");
r = sd_device_enumerator_add_match_subsystem(enumerate, "backlight", true);
r = sd_device_enumerator_add_match_subsystem(enumerate, "backlight", /* match = */ true);
if (r < 0)
return r;
return log_debug_errno(r, "Failed to add subsystem match: %m");
r = sd_device_enumerator_add_nomatch_sysname(enumerate, sysname);
if (r < 0)
return log_debug_errno(r, "Failed to add sysname unmatch: %m");
r = sd_device_enumerator_add_match_sysattr(enumerate, "type", "platform", /* match = */ true);
if (r < 0)
return log_debug_errno(r, "Failed to add sysattr match: %m");
r = sd_device_enumerator_add_match_sysattr(enumerate, "type", "firmware", /* match = */ true);
if (r < 0)
return log_debug_errno(r, "Failed to add sysattr match: %m");
if (streq(subsystem, "pci")) {
r = has_multiple_graphics_cards();
if (r < 0)
return log_debug_errno(r, "Failed to check if the system has multiple graphics cards: %m");
if (r > 0) {
/* If the system has multiple graphics cards, then we cannot associate platform
* devices on non-PCI bus (especially WMI bus) with PCI devices. Let's ignore all
* backlight devices that do not have the same parent PCI device. */
log_debug("Found multiple graphics cards on PCI bus. "
"Skipping to associate platform backlight devices on non-PCI bus.");
r = sd_device_enumerator_add_match_parent(enumerate, parent);
if (r < 0)
return log_debug_errno(r, "Failed to add parent match: %m");
}
}
FOREACH_DEVICE(enumerate, other) {
const char *other_subsystem;
sd_device *other_parent;
if (same_device(device, other) > 0)
continue;
if (sd_device_get_sysattr_value(other, "type", &v) < 0 ||
!STR_IN_SET(v, "platform", "firmware"))
continue;
/* OK, so there's another backlight device, and it's a platform or firmware device.
* Let's see if we can verify it belongs to the same device as ours. */
if (find_pci_or_platform_parent(other, &other_parent) < 0)
r = find_pci_or_platform_parent(other, &other_parent);
if (r < 0) {
log_device_debug_errno(other, r, "Failed to get PCI or platform parent, ignoring: %m");
continue;
}
if (same_device(parent, other_parent) > 0) {
const char *device_sysname = NULL, *other_sysname = NULL;
/* Both have the same PCI parent, that means we are out. */
if (DEBUG_LOGGING) {
const char *other_sysname = NULL, *other_type = NULL;
(void) sd_device_get_sysname(device, &device_sysname);
(void) sd_device_get_sysname(other, &other_sysname);
log_debug("Skipping backlight device %s, since device %s is on same PCI device and takes precedence.",
device_sysname, other_sysname);
(void) sd_device_get_sysname(other, &other_sysname);
(void) sd_device_get_sysattr_value(other, "type", &other_type);
log_device_debug(device,
"Found another %s backlight device %s on the same PCI, skipping.",
strna(other_type), strna(other_sysname));
}
return false;
}
if (sd_device_get_subsystem(other_parent, &other_subsystem) < 0)
r = sd_device_get_subsystem(other_parent, &other_subsystem);
if (r < 0) {
log_device_debug_errno(other_parent, r, "Failed to get subsystem, ignoring: %m");
continue;
}
if (streq(other_subsystem, "platform") && streq(subsystem, "pci")) {
const char *device_sysname = NULL, *other_sysname = NULL;
/* The other is connected to the platform bus and we are a PCI device, that also means we are out. */
if (DEBUG_LOGGING) {
const char *other_sysname = NULL, *other_type = NULL;
(void) sd_device_get_sysname(device, &device_sysname);
(void) sd_device_get_sysname(other, &other_sysname);
log_debug("Skipping backlight device %s, since device %s is a platform device and takes precedence.",
device_sysname, other_sysname);
(void) sd_device_get_sysname(other, &other_sysname);
(void) sd_device_get_sysattr_value(other, "type", &other_type);
log_device_debug(device,
"Found another %s backlight device %s, which has higher precedence, skipping.",
strna(other_type), strna(other_sysname));
}
return false;
}
}