Re: [PATCH v2 0/7] Modernize vga_switcheroo by using device link for HDA

[Daniel Vetter <daniel@ffwll.ch>]

On Sat, Mar 03, 2018 at 10:53:24AM +0100, Lukas Wunner wrote:
> Modernize vga_switcheroo by using a device link to enforce a runtime PM
> dependency from an HDA controller to the GPU it's integrated into, v2.
> 
> Changes since v1:
> 
> - Replace patch [1/7] to use pci_save_state() / pci_restore_state()
>   for consistency between runtime PM code path of bound and unbound
>   devices. (Rafael, Bjorn)
> 
> - Patch [5/7]: Drop an unnecessary initialization. (Bjorn)
>   Rephrase error message on failed link addition for clarity.
> 
> Link to v1:
> https://www.spinics.net/lists/dri-devel/msg165889.html
> 
> Testing on more machines would be greatly appreciated, particularly
> Nvidia Optimus or AMD PowerXpress.
> 
> The series is based on 4.16-rc3.  To test it on 4.15, you need to
> cherry-pick 7506dc798993 and 2fa6d6cdaf28.  For your convenience
> I've pushed a 4.15-based branch to:
> https://github.com/l1k/linux/commits/switcheroo_devlink_v2
> 
> Minimal test procedure:
> 
> - Note well: Recent Optimus require that a Mini-DP or HDMI cable is
>   plugged in on boot for the HDA device to be present.
> 
> - Check that HDA, GPU and root port autosuspend when not in use:
>   cat /sys/bus/pci/devices/0000:01:00.1/power/runtime_status  # HDA
>   cat /sys/bus/pci/devices/0000:01:00.0/power/runtime_status  # GPU
>   cat /sys/bus/pci/devices/0000:00:01.0/power/runtime_status  # Root Port
> 
> - Check that all three autoresume when accessing the HDA:
>   hdajacksensetest -c 1
> 
> - Unbind the HDA controller:
>   echo 0000:01:00.1 > /sys/bus/pci/drivers/snd_hda_intel/unbind
>   Wait for GPU to power off, then rebind the HDA controller:
>   echo 0000:01:00.1 > /sys/bus/pci/drivers/snd_hda_intel/bind
>   Check dmesg for errors, try accessing HDA with hdajacksensetest.
> 
> - If your laptop uses the root port's _PR3 to cut power to the GPU:
>   Unbind the GPU:
>   echo 0000:01:00.0 > /sys/bus/pci/drivers/{nouveau,amdgpu,radeon}/unbind
>   Allow runtime PM on the GPU:
>   echo auto > /sys/bus/pci/devices/0000:01:00.0/power/control
>   Wait for GPU to power off, then rebind it:
>   echo 0000:01:00.0 > /sys/bus/pci/drivers/{nouveau,amdgpu,radeon}/bind
>   Check dmesg for errors.  If you see any then we may need to perform
>   further actions in pci_pm_runtime_resume(), see patch [1/7].

This all looks really reasonable and like a good cleanup, but it's a bit
too much detail so I'll punt review to someone else with more clue.
-Daniel

> 
> Thanks,
> 
> Lukas
> 
> 
> Lukas Wunner (6):
>   PCI: Make pci_wakeup_bus() & pci_bus_set_current_state() public
>   vga_switcheroo: Update PCI current_state on power change
>   vga_switcheroo: Deduplicate power state tracking
>   vga_switcheroo: Use device link for HDA controller
>   vga_switcheroo: Let HDA autosuspend on mux change
>   drm/nouveau: Runtime suspend despite HDA being unbound
> 
> Rafael J. Wysocki (1):
>   PCI: Restore config space on runtime resume despite being unbound
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c |   2 -
>  drivers/gpu/drm/nouveau/nouveau_drm.c   |  46 ----------
>  drivers/gpu/drm/nouveau/nouveau_drv.h   |   1 -
>  drivers/gpu/drm/radeon/radeon_drv.c     |   2 -
>  drivers/gpu/vga/vga_switcheroo.c        | 152 ++++++++------------------------
>  drivers/pci/pci-driver.c                |  17 ++--
>  drivers/pci/pci.c                       |   8 +-
>  drivers/pci/quirks.c                    |  39 ++++++++
>  include/linux/pci.h                     |   2 +
>  include/linux/pci_ids.h                 |   1 +
>  include/linux/vga_switcheroo.h          |   6 --
>  include/sound/hdaudio.h                 |   3 -
>  sound/pci/hda/hda_intel.c               |  36 +++++---
>  sound/pci/hda/hda_intel.h               |   3 -
>  14 files changed, 117 insertions(+), 201 deletions(-)
> 
> -- 
> 2.15.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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