在 2018/7/16 22:02, Lukas Wunner 写道:
On Sat, Jul 14, 2018 at 02:15:24PM +0800, jimqu wrote:
??? 2018/7/13 17:27, Lukas Wunner ??????:
On Fri, Jul 13, 2018 at 04:06:02PM +0800, Jim Qu wrote:
On modern laptop, there are more and more platforms have two GPUs, and each of them maybe have audio codec for HDMP/DP output. For some dGPU which is no output, audio codec usually is disabled.
In currect HDA audio driver, it will set all codec as VGA_SWITCHEROO_DIS, the audio which is binded to UMA will be suspended if user use debugfs to contorl power
In HDA driver side, it is difficult to know which GPU the audio has binded to. So set the bound gpu pci dev to vgaswitchroo, the correct audio id will be set in vgaswitchreoo enable function.
Signed-off-by: Jim Qu Jim.Qu@amd.com
The approach you've taken in this patch won't work if the HDA controller is bound to a driver after both GPUs have already been bound to a driver and the handler has already been registered.
That's because vga_switcheroo_enable() is run when two GPUs have registered as clients and the handler has also registered. If the HDA controller is probed afterwards, its ID will be stuck at VGA_SWITCHEROO_UNKNOWN_ID.
In genernic speaking, there are two cases , a. audio client is the third client. b. audio client is not the third client.
if audio is third client. vga_switcheroo_ready() is true, vga_switcheroo_enable() can be called in audio client register fuction. if audio is not the third client, vga_switcheroo_enable() will be called in the second GFX client register. In vga_switcheroo_enable() , the first list loop will set two GPU clients' id, and the second list loop will select audio client, set id by its bound gpu pci dev.
No, if audio is the third client, vga_switcheroo_ready() is *not* true because vgasr_priv.active is true. This is set to true once the two GPUs and the handler have registered. If the audio device registers afterwards, vga_switcheroo_enable() will already have been called. It's never called twice because it sets vgasr_priv.active = true.
As a result, the audio device is stuck at VGA_SWITCHEROO_UNKNOWN_ID.
Indeed, I almost ignore the vgasr_priv.active, since I added amdgpu to blacklist, audio is always the first client. :). not so bad, Let me rework the patch tomorrow.
Thanks JimQu
Thanks,
Lukas