On Mon, Jan 23, 2023 at 01:38:37PM +0100, Hans de Goede wrote: > On 1/23/23 13:09, Lukas Wunner wrote: > > On Mon, Jan 23, 2023 at 12:37:47PM +0100, Hans de Goede wrote: > > > Some apple laptop models have an ACPI device with a HID of APP000B > > > and that device has an IO resource (so it does not describe the new > > > unsupported MMIO based gmux type), but there actually is no gmux > > > in the laptop at all. > > > > > > This patch-series improves the drivers/acpi/video_detect.c so that > > > it no longer tries to use the non present gmux in this case. > > > > > > Note I'm still waiting for testing feedback from the reporter of > > > this problem. But from the logs the problem is clear > > > (the logs show: "apple_gmux: gmux device not present") > > > > Please provide a link to the original report. I would also like to > > know the exact MacBook model used and I would like to see full dmesg > > output as well as an acpidump. > > I only have a report by private email. This does include full dmesg > output and an acpidump. I will forward this to you in a private > email. > > The reporter describes their model as a macbookpro8,1. > > > What you're saying here is that there's a fake APP000B device present > > in DSDT > > Yes that is exactly what I'm saying. That's a 2011 13" MacBook Pro which indeed does not have dual GPUs. I searched for other affected models and this seems to be more common than I thought: MacBookPro5,4 https://pastebin.com/8Xjq7RhS MacBookPro8,1 https://linux-hardware.org/?probe=e513cfbadb&log=dmesg MacBookPro9,2 https://bugzilla.kernel.org/attachment.cgi?id=278961 MacBookPro10,2 https://lkml.org/lkml/2014/9/22/657 MacBookPro11,2 https://forums.fedora-fr.org/viewtopic.php?id=70142 MacBookPro11,4 https://raw.githubusercontent.com/im-0/investigate-card-reader-suspend-problem-on-mbp11.4/master/test-16/dmesg These are 13" and 15" models from the pre-retina and retina era (2009 - 2015). None of them have dual GPUs. (Only a subset of the 15" and 17" models had dual GPUs.) Apple sloppily included a GMUX device on all of them and it wasn't a problem so far because the gmux driver detects non-presence and bails out, but it throws off the new backlight algorithm. This is really sad. :( Please add a Reported-by to your commits as well as the list I've provided above so that we've got a complete record in the git history. Thanks, Lukas
