[SRU][Bionic][PATCH 0/2] HDMI/DP audio can't work on the laptop of Dell Latitude 5495

[Khaled Elmously]

Hui, this seems to break the build for me. Could you please confirm that it builds fine for you?

This is what I get:

/tmp/kernel-kmously-60a6102-lUVu/build/drivers/gpu/drm/nouveau/nouveau_acpi.c:212:19: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
  .get_client_id = nouveau_dsm_get_client_id,
                   ^~~~~~~~~~~~~~~~~~~~~~~~~
/tmp/kernel-kmously-60a6102-lUVu/build/drivers/gpu/drm/nouveau/nouveau_acpi.c:212:19: note: (near initialization for 'nouveau_dsm_handler.get_client_id')
cc1: some warnings being treated as errors
/tmp/kernel-kmously-60a6102-lUVu/build/scripts/Makefile.build:332: recipe for target 'drivers/gpu/drm/nouveau/nouveau_acpi.o' failed
make[6]: *** [drivers/gpu/drm/nouveau/nouveau_acpi.o] Error 1
make[6]: *** Waiting for unfinished jobs....
/tmp/kernel-kmously-60a6102-lUVu/build/scripts/Makefile.build:606: recipe for target 'drivers/gpu/drm/nouveau' failed
make[5]: *** [drivers/gpu/drm/nouveau] Error 2
/tmp/kernel-kmously-60a6102-lUVu/build/scripts/Makefile.build:606: recipe for target 'drivers/gpu/drm' failed
make[4]: *** [drivers/gpu/drm] Error 2
/tmp/kernel-kmously-60a6102-lUVu/build/scripts/Makefile.build:606: recipe for target 'drivers/gpu' failed
make[3]: *** [drivers/gpu] Error 2
/tmp/kernel-kmously-60a6102-lUVu/build/Makefile:1060: recipe for target 'drivers' failed
make[2]: *** [drivers] Error 2
make[2]: Leaving directory '/tmp/kernel-kmously-60a6102-lUVu/build/debian/build/build-generic'
Makefile:146: recipe for target 'sub-make' failed
make[1]: *** [sub-make] Error 2
make[1]: Leaving directory '/tmp/kernel-kmously-60a6102-lUVu/build'
debian/rules.d/2-binary-arch.mk:70: recipe for target '/tmp/kernel-kmously-60a6102-lUVu/build/debian/stamps/stamp-build-generic' failed
make: *** [/tmp/kernel-kmously-60a6102-lUVu/build/debian/stamps/stamp-build-generic] Error 2
+++gbk++++ build exit status was 2



On 2018-07-20 14:41:21 , Hui Wang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1782689
> 
> This bug comes from the OEM project, and the engineer Jim Qu from AMD took
> almost 2 weeks to investigate this problem, then he worte these two patches to
> fix this problem and now the patches are merged to sound repository.
> 
> According to Jim Qu's investigation, the root cause of this problem is:
> 1. there is two GPU on the system. iGPU has a audio codec for HDMI output,
>    and dGPU is without audio codec it is only for offload rendering.
> 2. under runtime pm, when dGPU suspend, amdgpu will also call vgaswitchroo
>    driver to power off audio which vgaswitchroo client is VGA_SWITCHEROO_DIS.
> 3. In current HDA audio driver, the iGPU's audio will register to vgaswitchroo
>    as VGA_SWITCHEROO_DIS, therefore, the audio will be selected and powered off
>    by runtime pm.
> 
> [Impact]
> On the Dell Latitude 5495, If we plug a monitor with audio capability to the
> HDMI/DP ports, we can't find HDMI/DP audio sinks as expected, then we can't
> play any sound through HDMI/DP audio.
> 
> [Fix]
> With these two patches, the driver will not always set vgaswicheroo clients of
> HDA audio as VGA_SWITCHEROO_DIS, it will set it to _DIS or _IGD with the help
> of callback function of DRM drivers. So on this machine, the vgaswicheroo client
> will be set _IGD, then it will not be powered off when discrete gpu is powered off. 
> 
> [Test Case]
> We tested plug/unplug detection and playback through HDMI/DP audio, everything works
> well.
> 
> [Regression Potential]
> Very low, without these two patches, the vgaswitchroo client of audio will be
> set to _DIS unconditionally, it did not expose any problem because in the past,
> all the HDMI/DP audio codecs are in the discreate GPU. But on Latitude 5495, the
> HDMI/DP audio codec is in the integrated GPU, so we need to change the driver to
> let DRM driver decide if it is _DIS or _IGD, it will not introduce regression for
> old mahcines on old machines, the client will be set to _DIS as before.
> 
> And we have tested these two patches on some old machines with two gpus like A+A
> , I+A and I+N, all of them worked well as before.
> 
> 
> Jim Qu (2):
>   ALSA: hda: use PCI_BASE_CLASS_DISPLAY to replace PCI_CLASS_DISPLAY_VGA
>   vga_switcheroo: set audio client id according to bound GPU id
> 
>  drivers/gpu/vga/vga_switcheroo.c | 62 +++++++++++++++++++++++++++++++++-------
>  include/linux/vga_switcheroo.h   |  8 +++---
>  sound/pci/hda/hda_intel.c        | 13 +++++----
>  3 files changed, 62 insertions(+), 21 deletions(-)
> 
> -- 
> 2.7.4
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team