We've several reports from users where the backlight comes up turned off on starting X, when using video.use_native_backlight=1 (true dmi quirks, will be the default for 3.16), in combination with having an external display plugged in: https://bugzilla.redhat.com/show_bug.cgi?id=1032978 https://bugzilla.redhat.com/show_bug.cgi?id=1103806 This seems to be caused by /sys/class/backlight/intel_backlight/brightness reading back 0 when re-initializing the outputs. Unlike /sys/class/backlight/acpi_video0/brightness which is used without the video.use_native_backlight=1 param, which keeps returning the value from before Here is an excerpt from Xorg.log when this happens: [28225]: (II) intel(0): resizing framebuffer to 3286x1080 [28225]: (II) intel(0): switch to mode 1366x768@59.8 on pipe 0 using LVDS1, position (0, 0), rotation normal [28225]: (II) intel(0): switch to mode 1920x1080@60.0 on pipe 0 using HDMI2, position (1366, 0), rotation normal [28225]: (II) intel(0): DPMS off mode 3, saved backlight level 0 ^^^ This is an extra debug line I added, mode == the mode parameter to xxx_output_dpms_backlight, saved backlight level is the value of backlight_active_level after the xxx_output_backlight_get call. Note how backlight_active_level becomes 0 here. [28225]: (II) intel(0): switch to mode 1366x768@59.8 on pipe 1 using LVDS1, position (0, 0), rotation normal [28225]: (II) intel(0): DPMS on mode 0, setting backlight to 0 And here we restore the backlight to backlight_active_level which now is 0. This commit fixes this by not reading back the backlight setting from the kernel on DPMS off. Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> --- src/sna/sna_display.c | 3 --- src/uxa/intel_display.c | 3 --- 2 files changed, 6 deletions(-) diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c index 13dbf64..c9d4b08 100644 --- a/src/sna/sna_display.c +++ b/src/sna/sna_display.c @@ -2323,9 +2323,6 @@ sna_output_dpms_backlight(xf86OutputPtr output, int oldmode, int mode) sna_output_backlight_set(output, sna_output->backlight_active_level); } else { - /* Only save the current backlight value if we're going from on to off. */ - if (oldmode == DPMSModeOn) - sna_output->backlight_active_level = sna_output_backlight_get(output); sna_output_backlight_set(output, 0); } } diff --git a/src/uxa/intel_display.c b/src/uxa/intel_display.c index 95ddcc8..62902f4 100644 --- a/src/uxa/intel_display.c +++ b/src/uxa/intel_display.c @@ -963,9 +963,6 @@ intel_output_dpms_backlight(xf86OutputPtr output, int oldmode, int mode) intel_output_backlight_set(output, intel_output->backlight_active_level); } else { - /* Only save the current backlight value if we're going from on to off. */ - if (oldmode == DPMSModeOn) - intel_output->backlight_active_level = intel_output_backlight_get(output); intel_output_backlight_set(output, 0); } } -- 2.0.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
