On Friday, September 26, 2014 10:30:08 AM Aaron Lu wrote: > Some of the Thinkpads' firmware will issue a backlight change request > through i915 operation region unconditionally on AC plug/unplug, the > backlight level used is arbitrary and thus should be ignored. This is > handled by commit 0b9f7d93ca61 (ACPI / i915: ignore firmware requests > for backlight change). Then there is a Dell laptop whose vendor backlight > interface also makes use of operation region to change backlight level > and with the above commit, that interface no long works. The condition > used to ignore the backlight change request from firmware is thus > changed to: if the vendor backlight interface is not in use and the ACPI > backlight interface is broken, we ignore the requests; oterwise, we keep > processing them. > > Reference: https://lkml.org/lkml/2014/9/23/854 > Reported-and-tested-by: Pali Rohár <pali.rohar@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> # v3.16 and later > Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> Daniel, any objections? > --- > drivers/gpu/drm/i915/intel_opregion.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c > index ca52ad2ae7d1..d8de1d5140a7 100644 > --- a/drivers/gpu/drm/i915/intel_opregion.c > +++ b/drivers/gpu/drm/i915/intel_opregion.c > @@ -396,6 +396,16 @@ int intel_opregion_notify_adapter(struct drm_device *dev, pci_power_t state) > return -EINVAL; > } > > +/* > + * If the vendor backlight interface is not in use and ACPI backlight interface > + * is broken, do not bother processing backlight change requests from firmware. > + */ > +static bool should_ignore_backlight_request(void) > +{ > + return acpi_video_backlight_support() && > + !acpi_video_verify_backlight_support(); > +} > + > static u32 asle_set_backlight(struct drm_device *dev, u32 bclp) > { > struct drm_i915_private *dev_priv = dev->dev_private; > @@ -404,11 +414,7 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp) > > DRM_DEBUG_DRIVER("bclp = 0x%08x\n", bclp); > > - /* > - * If the acpi_video interface is not supposed to be used, don't > - * bother processing backlight level change requests from firmware. > - */ > - if (!acpi_video_verify_backlight_support()) { > + if (should_ignore_backlight_request()) { > DRM_DEBUG_KMS("opregion backlight request ignored\n"); > return 0; > } > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
