On Mon, Jul 9, 2018 at 6:16 AM, Qu, Jim <jim...@amd.com> wrote: > Hi Lukas, > > Thanks to your explanation, and see comments in line. > > > Do you need to runtime resume the HDA controller even if user space isn't > streaming audio? Why, and in which situation exactly? > > Jim: OEM system uses pactl to queiry audio card and audio output sink, since > the audio has power down by runtime pm, so the audio card and output sink are > all unavailable. they could not select the available HDMI audio for audio > playing.
Sounds like a bug in the HDA driver. The HDA driver should cache what it needs or power it back up when there is an ioctl/etc. that requires something that can't be cached. Alex > > 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? > > Jim: 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. > > Thanks > JimQu > > ________________________________________ > 发件人: Lukas Wunner <lu...@wunner.de> > 发送时间: 2018年7月9日 17:27 > 收件人: Qu, Jim > 抄送: alsa-de...@alsa-project.org; dri-devel@lists.freedesktop.org; Deucher, > Alexander; amd-...@lists.freedesktop.org > 主题: Re: [PATCH] vgaswitchroo: set audio client id according to bound gpu > client id > > On Mon, Jul 09, 2018 at 08:52:33AM +0000, Qu, Jim wrote: >> Now, I found the audio device will auto suspend even if the gpu is active, >> and if I plug in a HDMI device it also do not resume back. >> >> 1. Did you encounter similar issue before? >> 2. audio will auto suspend as default at beginning of boot, is it expect >> behaviour? > > Yes, that's expected. Once you start streaming audio to attached displays, > user space opens the codec device and this causes the HDA controller to > runtime resume. If the discrete GPU is suspended at that moment, it will > be powered on and kept powered on as long as user space is streaming audio. > > Do you need to runtime resume the HDA controller even if user space isn't > streaming audio? Why, and in which situation exactly? > > 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? > > Thanks, > > Lukas > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
