Re: [PATCH 0/3] ACPI: video/apple-gmux: Improve apple-gmux backlight detection

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 1/23/23 14:58, Lukas Wunner wrote:
> 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

I was about to say that Emmanouil may want to keep their email
private. But I see you've already added them to the Cc, so
now the email is part of the platform-driver-x86 archives.

Emmanouil, is it ok if I add a line like this:

Reported-by: Emmanouil Kouroupakis <kartxxx@gmail.com>

to the commit message of v2 of the patches ? This gives you credit
for reporting the bug, but it also exposes your email address
in public places.

> as well as the list I've
> provided above so that we've got a complete record in the git history.

Ack, I'll add the list of devices to v2 of the patches.

Regards,

Hans