On Thursday, September 25, 2014 11:15:35 AM Aaron Lu wrote: > Hi Hans, > > Thanks for following up and explaining the situation to Pali. > > On 09/25/2014 02:21 AM, Pali Rohár wrote: > > On Wednesday 24 September 2014 16:34:21 Hans de Goede wrote: > >> Ok, so the dell-laptop interface is just an obsolete wrapper > >> around the i915 opregion code, which shows that the right > >> interface to use is the i915 one, which we do if you don't > >> specify any kernel commandline parameters, case closed. > >> > >> Regards, > >> > >> Hans > > > > Nope, its not closed. > > > > Still i915 interface has problem with setting backlight. It > > exports lot of levels which turning display off. Which breaking > > exiting applications for configuring display brightness. This is > > still big regression as black screen is not want people want to > > see. > > > > Driver dell-laptop has exported only few - not thousands level > > (which is insane) and only usefull levels (not lot of levels > > which turn display off). > > > > So for this reason using i915 backlight interface is not possible > > and also Dell (for E6440) set kernel param acpi_backlight=vendor > > to use dell_laptop module for controlling brightness. > > > > On my laptop E6440 is better for using dell-laptop and not acpi > > or i915. > > Hi Pali, > > Please test this patch: > > diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c > index ca52ad2ae7d1..15534345bd57 100644 > --- a/drivers/gpu/drm/i915/intel_opregion.c > +++ b/drivers/gpu/drm/i915/intel_opregion.c > @@ -396,6 +396,24 @@ int intel_opregion_notify_adapter(struct drm_device *dev, pci_power_t state) > return -EINVAL; > } > > +/* > + * Some of the Thinkpads' firmware will issue a backlight change operation > + * region request unconditionally on AC plug/unplug, this is undesirable and > + * should be ignored. Then there is a Dell laptop whose vendor backlight > + * interface also makes use of operation region request to change backlight > + * level and we have to keep it work. The rule used here is: 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. > + */ > +static bool should_ignore_backlight_request(void) > +{ > + if (acpi_video_backlight_support() && > + !acpi_video_verify_backlight_support()) > + return true; > + > + return false; > +} Well, what about 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 +422,7 @@ 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; > } > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel