On 05/14/2014 07:09 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 Reading your other reply, I thought you already figured this out so I didn't explain, sorry for that. > 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? Unfortunately, there are indeed systems that with Intel GFX do not have a GPU backlight control interface: commit c675949ec58ca50d5a3ae3c757892f1560f6e896 Author: Jani Nikula <jani.nikula@xxxxxxxxx> Date: Wed Apr 9 11:31:37 2014 +0300 drm/i915: do not setup backlight if not available according to VBT And I remembered last time when we push the use_native default to 1 without checking if a raw interface is available, there are people complaining about no backlight interface is created on his system(and the only working interface is acpi_video on his Win8 system). So simply dropping this check doesn't seem like a good idea. Thanks, Aaron > 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. > > Regards, > > Hans > > > > > > >> >> Regards, >> >> Hans >> >> >> >>> >>> Thanks, >>> Aaron >>> >>>> >>>> https://bugzilla.redhat.com/show_bug.cgi?id=1093171 >>>> >>>> Cc: stable@xxxxxxxxxxxxxxx >>>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >>>> --- >>>> drivers/acpi/video.c | 8 ++++++++ >>>> 1 file changed, 8 insertions(+) >>>> >>>> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c >>>> index 34198b2..6a2099d 100644 >>>> --- a/drivers/acpi/video.c >>>> +++ b/drivers/acpi/video.c >>>> @@ -520,6 +520,14 @@ static struct dmi_system_id video_dmi_table[] __initdata = { >>>> }, >>>> }, >>>> { >>>> + .callback = video_set_use_native_backlight, >>>> + .ident = "ThinkPad W530", >>>> + .matches = { >>>> + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), >>>> + DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad W530"), >>>> + }, >>>> + }, >>>> + { >>>> .callback = video_set_use_native_backlight, >>>> .ident = "ThinkPad X1 Carbon", >>>> .matches = { >>>> >>> -- 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
