On Wednesday, May 14, 2014 01:09:33 PM Hans de Goede wrote: > Hi, > > On 05/12/2014 01:02 PM, Hans de Goede wrote: > > Hi, > > > > On 05/12/2014 10:16 AM, Aaron Lu wrote: > >> On 05/12/2014 03:57 PM, Hans de Goede wrote: > >>> Like all of the other *30 ThinkPad models, the W530 has a broken acpi-video > >>> backlight control. Note in order for this to actually fix things on the > >>> ThinkPad W530 the commit titled: > >>> "nouveau: Don't check acpi_video_backlight_support() before registering backlight" > >>> is also needed. > >> > >> Note that the backlight_device_registered(raw) may return false as when > >> acpi_video_verify_backlight_support is called, the nouveau driver may > >> not run yet. > >> > >> Previously, we don't know anything about how laptops with nvidia graphics > >> card alone control backlight in Win8, so the existing solution doesn't > >> consider this case. If nvidia graphics system also should favour native > >> backlight control interface in Win8, the current solution needs > >> modifications. > > > > Hmm, how is this dealt with in the case of the intel gfx driver ? > > Ok, I've figured out now how this is dealt with in the case of the intel gfx > drivers. That looks like something which will likely be hard to do for > nouveau, since it relies on some intel gfx specific ACPI calls being there, > which nouveau does not have. So this would require doing something like > duplicating the nouveau pci-ids or some such, which would be far from ideal. > > Still this bug: https://bugzilla.redhat.com/show_bug.cgi?id=1093171 > > Shows that we need *working* video.use_native_brightness=1 support for > non intel too. Which the current loading order issues caused by the > backlight_device_registered(raw) breaks. > > So maybe we should simply drop the backlight_device_registered(raw) check? > I don't think we really need it any win8 supporting laptop will have > intel, nv or ati gfx, and all 3 of them have native backlight support, > which if our experiences so far is any indication we will likely want > to use instead of acpi_video. We can try that, but if it turns out to break things for someone, we'll need a different approach. Thanks! -- 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
