On Wed, Feb 29, 2012 at 4:08 PM, Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote: > On Wed, Feb 29, 2012 at 03:23:20PM -0600, Grant Likely wrote: >> On Wed, Feb 29, 2012 at 1:50 PM, Seth Forshee >> <seth.forshee@xxxxxxxxxxxxx> wrote: >> > On Wed, Feb 29, 2012 at 12:43:23PM -0600, Grant Likely wrote: >> >> On Wed, Feb 29, 2012 at 11:53 AM, Seth Forshee >> >> <seth.forshee@xxxxxxxxxxxxx> wrote: >> >> > On Wed, Feb 29, 2012 at 11:46:39AM -0600, Grant Likely wrote: >> >> >> On Wed, Feb 22, 2012 at 8:37 AM, Seth Forshee >> >> >> <seth.forshee@xxxxxxxxxxxxx> wrote: >> >> >> > Apple laptops with hybrid graphics have a device named gmux that >> >> >> > controls the muxing of the LVDS panel between the GPUs as well as screen >> >> >> > brightness. This driver adds support for the gmux device. Only backlight >> >> >> > control is supported initially. >> >> >> > >> >> >> > Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> >> >> >> >> >> >> Works for me. >> >> >> >> >> >> Tested-by: Grant Likely <grant.likely@xxxxxxxxxxxx> >> >> >> >> >> >> Now I just need to figure out how to get the desktop backlight widget >> >> >> to use gmux_backlight instead of acpi_video0... >> >> > >> >> > The easy way is to pass acpi_backlight=vendor to the kernel, then you >> >> > won't have acpi_vidoe0. >> >> >> >> That did it, thanks. I'm assume something is in the works to set it >> >> up automatically? >> > >> > Not that I'm aware of. A number machines have this problem, that the >> > standard ACPI backlight interfaces are implemented but don't work. This >> > generally isn't detectable in software; with the Apples at least >> > everything looks like it's working except that the brightness doesn't >> > change (but not all Apple laptops are affected, so qurking based on >> > manufacturer wouldn't work). All we're left with is DMI quirking, which >> > isn't practical. Maybe we could add something so a platform driver can >> > tell acpi_video that it knows the ACPI backlight doesn't work, but I >> > think on some platforms that still is going to be based off of DMI >> > information. >> >> blacklisting based on specific product name (ie. MacBookPro8,*) or >> machine model is probably the best. It wouldn't be the first >> blacklist in the linux kernel. > > I think the blacklist would have to be against specific product names. > For example, the MacBook Pro 8,1 has a working acpi_video backlight and > no gmux_backlight, the 8,2 has both but only gmux_backlight works, and I > suspect the 8,3 is the same as the 8,2. I have the 8,3, and my testing confirms that. > We'd probably end up with an > entry in the blacklist for every single model whose acpi_video backlight > doesn't work, adding entries for each new generation of MacBooks. > > And if we start blacklisting Macs we'd have start doing it for other > machines too, I guess. From what I've seen, open-ended blacklists like > this get nacked pretty consistently nowadays. An alternative would be to blacklist or disable acpi0_backlight when the apple-gmux driver loads. I don't know how acceptable that is, but I also don't have much sympathy for nacking blacklists if there isn't a viable alternative. g. -- Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd. -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
