Hi All, Here, I want to clarify the audio device is bound to iGPU. There is no audio codec for dGPU. Thanks JimQu -----邮件原件----- 发件人: Lukas Wunner <lukas@xxxxxxxxx> 发送时间: 2018年7月9日 23:48 收件人: Takashi Iwai <tiwai@xxxxxxx> 抄送: Alex Deucher <alexdeucher@xxxxxxxxx>; alsa-devel@xxxxxxxxxxxxxxxx; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Qu, Jim <Jim.Qu@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; Deucher, Alexander <Alexander.Deucher@xxxxxxx> 主题: Re: [alsa-devel] ??????: [PATCH] vgaswitchroo: set audio client id according to bound gpu client id On Mon, Jul 09, 2018 at 05:04:22PM +0200, Takashi Iwai wrote: > On Mon, 09 Jul 2018 15:58:51 +0200, Alex Deucher wrote: > > On Mon, Jul 9, 2018 at 6:16 AM, Qu, Jim <Jim.Qu@xxxxxxx> wrote: > > > > You're saying above that the HDA controller isn't runtime > > > > resumed on hotplug of a display. Is that necessary to retrieve ELD or something? > > > > I'm not sure if there's code in the HDA driver to acquire a > > > > runtime PM ref on HPD, but maybe it's necessary. Or maybe the > > > > code is there but somehow no HPD interrupt is received by the HDA driver? > > > > > > So far, I do not find any code about audio response HPD in kernel. > > > the HPD interrupt will sent to user mode via uevent, not sure > > > whether audio user mode driver can receive the event or not. > > > > On the gfx side at least, we can get a hotplug event via ACPI > > (depending on the OEM design) if displays are attached/detached > > while the dGPU is powered down. I suppose the gfx driver could call > > into the audio driver during one of those events. On the gfx side > > at least we just generate the gfx hotplug event and let userspace deal with it. > > IMO, a more proper way would be to have the direct communication > between the graphics driver and the audio driver like i915 driver > does. Then the audio driver can get plug/unplug event at more > accurate timing without races. Since v4.17, every time the GPU is powered up, the HDA controller is runtime resumed to PCI_D0. (See the call to pci_wakeup_bus() in vga_switcheroo_runtime_resume() added by dcac86b7d0.) If the HDA controller can't detect presence of an HDMI display even if it's in PCI_D0, then I suppose that needs to be adressed in the HDA driver. Thus so far I don't see the need to call from amdgpu into the HDA driver. Thanks, Lukas _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
