On Sun, Aug 5, 2012 at 5:44 PM, Dave Airlie <airlied@xxxxxxxxx> wrote: > On Mon, Aug 6, 2012 at 7:40 AM, Daniel Vetter <daniel@xxxxxxxx> wrote: >> On Sun, Aug 05, 2012 at 10:18:38PM +0100, Matthew Garrett wrote: >>> On Sun, Aug 05, 2012 at 11:14:12PM +0200, Daniel Vetter wrote: >>> >>> > I like this approach more - the only other solution I see is to ask the >>> > currently active driver (i.e. radeon) at bootime for the right mode. Which >>> > sounds much more hellish and fragile ... >>> >>> The "correct" approach is clearly to just have the drm core change the >>> i2c mux before requesting edid, but that's made difficult because of the >>> absence of ordering guarantees in initialisation. I don't like quirking >>> this, since we're then back to the situation of potentially having to >>> add every new piece of related hardware to the quirk list. >> >> The "correct" approach of switching the mux before we fetch the edid is >> actualy the one I fear will result in fragile code: Only run on few >> machines, and as you say with tons of funky interactions with the init >> sequence ordering. And I guess people will bitch&moan about the flickering >> this will cause ;-) >> >> As long as it's only apple shipping multi-gpu machines with >> broken/non-existing vbt, I'll happily stomach the quirk list entries. >> They're bad, but imo the lesser evil. > > Well in theory you can switch the ddc lines without switching the other lines, > so we could do a mutex protected mux switch around edid retrival, > Depends on the system. On non-Macs, some systems have a single mux, others have a separate mux for i2c and display as specified in the ATPX ACPI methods. Not sure how the Macs do it. I've started cleaning up the PX radeon code along with a bunch of other radeon ralated ACPI fixes: http://cgit.freedesktop.org/~agd5f/linux/log/?h=acpi_patches Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
