Backlight control broken on UM325 (OLED) on 5.15 (bisected)

[Samuel Čavoj]

Hi Roman,

On 17.11.2021 15:26, Li, Roman wrote:
> [Public]
> 
> Hi Samuel,
> 
> Can you please try: https://patchwork.freedesktop.org/patch/463485/ ?

Yup, that did the trick. Works as before. Thank you very much.

Samuel

> 
> Thanks,
> Roman
> 
> > -----Original Message-----
> > From: Samuel Čavoj <samuel at cavoj.net>
> > Sent: Tuesday, November 16, 2021 8:33 AM
> > To: Alex Deucher <alexdeucher at gmail.com>
> > Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; Li, Sun peng (Leo)
> > <Sunpeng.Li at amd.com>; Li, Roman <Roman.Li at amd.com>; Maling list - DRI
> > developers <dri-devel at lists.freedesktop.org>; LKML <linux-
> > kernel at vger.kernel.org>; amd-gfx list <amd-gfx at lists.freedesktop.org>
> > Subject: Re: Backlight control broken on UM325 (OLED) on 5.15 (bisected)
> >
> > Hi Alex,
> >
> > thank you for your response.
> >
> > On 15.11.2021 10:43, Alex Deucher wrote:
> > > [...]
> > >
> > > That patch adds support for systems with multiple backlights.  Do you
> > > have multiple backlight devices now?  If so, does the other one work?
> >
> > No, there is still only one backlight device -- amdgpu_bl0.
> > >
> > > Can you also try this patch?
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > > index 4811b0faafd9..67163c9d49e6 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c
> > > @@ -854,8 +854,8 @@ int amdgpu_acpi_init(struct amdgpu_device *adev)
> > >                 if (amdgpu_device_has_dc_support(adev)) {  #if
> > > defined(CONFIG_DRM_AMD_DC)
> > >                         struct amdgpu_display_manager *dm = &adev->dm;
> > > -                       if (dm->backlight_dev[0])
> > > -                               atif->bd = dm->backlight_dev[0];
> > > +                       if (dm->backlight_dev[1])
> > > +                               atif->bd = dm->backlight_dev[1];
> > >  #endif
> > >                 } else {
> > >                         struct drm_encoder *tmp;
> > >
> >
> > There is no difference in behaviour after applying the patch.
> >
> > Samuel
> >
> > >
> > > Alex
> > >
> > > >
> > > > Regards,
> > > > Samuel Čavoj
> > > >
> > > > [0]:
> > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww
> > > >
> > w.reddit.com%2Fr%2FAMDLaptops%2Fcomments%2Fqst0fm%2Fafter_updating
> > _t
> > > >
> > o_linux_515_my_brightness%2F&data=04%7C01%7CRoman.Li%40amd.co
> > m%7
> > > >
> > Ce1c766a2f7014cdb664308d9a9059cc6%7C3dd8961fe4884e608e11a82d994e1
> > 83d
> > > >
> > %7C0%7C0%7C637726663861883494%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi
> > MC4wLj
> > > >
> > AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&s
> > dat
> > > >
> > a=hfsaEzng9%2FjAI2F%2BKg87Tv2Mu%2FfPurCQELr62%2B%2FVF%2BQ%3D&a
> > mp;res
> > > > erved=0