On Tue, 26 May 2015 22:35:46 -0700 Michael Marineau wrote: > On Tue, May 26, 2015 at 9:47 PM, Darren Hart <dvhart@xxxxxxxxxxxxx> wrote: > > On Tue, May 26, 2015 at 12:10:48PM -0700, Michael Marineau wrote: > >> FYI, this actually broke backlight controls on my MBP11,3 because the > >> assumption the patch makes that gmux is always loaded before graphics > >> drivers didn't hold true. At least for me dracut included the nouveau > >> module in the initrd but not gmux, ensuring the ordering was wrong. No > >> errors were reporting, and gmux still offered the backlight device, it > >> just became inoperable. I worked around this for my kernel by building > >> gmux into vmlinuz instead of as a module but that isn't going to in > >> more general configs because there is an apple backlight driver which > >> cannot be built at all in that configuration. > >> > > > > Thank you for reporting this Michael, > > > > That is tough as nouveau doesn't have an explicit dependency on gmux, so we > > could do something like a passive request_module(), but if it isn't in the > > initrd image, it would still fail as you describe. > > > >> Is there a way to make the ordering between nouveau and gmux more > >> explicit/reliable? Can gmux complain loudly if the ordering is ever > >> wrong? > > > > It should print an error if the probe fails due to the IO already being in use > > or if it can't be allocated. The disabled IO case is only info level though, > > perhaps that should be higher priority. Printing something when failing to probe > > seems like a reasonable thing to do. > > > > Michael, which message do you get if you boot with "debug" or "loglevel=6" when > > apple-gmux is not built-in? > > No error, gmux claims it worked: > [ 13.693379] apple_gmux: Found gmux version 4.0.8 [indexed] > [ 13.693400] vgaarb: device changed decodes: > PCI:0000:01:00.0,olddecodes=io+mem,decodes=io+mem:owns=none > [ 13.693404] apple_gmux: locked IO for PCI:0000:01:00.0 > > Full dmesg: https://gist.github.com/marineam/0e5a23548e8b3b2e1d50 What GPUs are there in your MBP11,3? From your dmesg it looks like all you have is NVIDIA GPU 0000:01:00.0 (lspci?). Is there a somehow hidden intel GPU around doing the backlight? If so my locking does the wrong thing for your system as: [ 0.393298] vgaarb: device added: PCI:0000:01:00.0,decodes=io+mem,owns=none,locks=none [ 0.393299] vgaarb: loaded [ 0.393300] vgaarb: setting as boot device: PCI:0000:01:00.0 [ 0.393301] vgaarb: bridge control possible 0000:01:00.0 ... [ 13.693379] apple_gmux: Found gmux version 4.0.8 [indexed] [ 13.693400] vgaarb: device changed decodes: PCI:0000:01:00.0,olddecodes=io+mem,decodes=io+mem:owns=none [ 13.693404] apple_gmux: locked IO for PCI:0000:01:00.0 Here it triggers "olddecodes=none -> io+mem". Making sure to lock only the intel GPU when present and especially protecting against nvidia driver will be hard if legacy-IO is being processed by a hidden device! Bruno -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
