On Mon, 28 Mar 2022 15:51:17 +0200, Mohan Kumar D wrote: > > > On 3/28/2022 4:27 PM, Takashi Iwai wrote: > > External email: Use caution opening links or attachments > > > > > > On Mon, 28 Mar 2022 12:19:03 +0200, > > Mohan Kumar D wrote: > >> > >> On 3/28/2022 3:12 PM, Takashi Iwai wrote: > >>> External email: Use caution opening links or attachments > >>> > >>> > >>> On Mon, 28 Mar 2022 11:14:11 +0200, > >>> Mohan Kumar wrote: > >>>> There is a corner case with unsol event handling during codec runtime > >>>> suspending state. When the codec runtime suspend call initiated, the > >>>> codec->in_pm atomic variable would be 0, currently the codec runtime > >>>> suspend function calls snd_hdac_enter_pm() which will just increments > >>>> the codec->in_pm atomic variable. Consider unsol event happened just > >>>> after this step and before snd_hdac_leave_pm() in the codec runtime > >>>> suspend function. The snd_hdac_power_up_pm() in the unsol event > >>>> flow in hdmi_present_sense_via_verbs() function would just increment > >>>> the codec->in_pm atomic variable without calling pm_runtime_get_sync > >>>> function. > >>>> > >>>> As codec runtime suspend flow is already in progress and in parallel > >>>> unsol event is also accessing the codec verbs, as soon as codec > >>>> suspend flow completes and clocks are switched off before completing > >>>> the unsol event handling as both functions doesn't wait for each other. > >>>> This will result in below errors > >>>> > >>>> [ 589.428020] tegra-hda 3510000.hda: azx_get_response timeout, switching > >>>> to polling mode: last cmd=0x505f2f57 > >>>> [ 589.428344] tegra-hda 3510000.hda: spurious response 0x80000074:0x5, > >>>> last cmd=0x505f2f57 > >>>> [ 589.428547] tegra-hda 3510000.hda: spurious response 0x80000065:0x5, > >>>> last cmd=0x505f2f57 > >>>> > >>>> To avoid this, the unsol event flow should not perform any codec verb > >>>> related operations during RPM_SUSPENDING state. > >>>> > >>>> Signed-off-by: Mohan Kumar <mkumard@xxxxxxxxxx> > >>> Thanks, that's a hairy problem... > >>> > >>> The logic sounds good, but can we check the PM state before calling > >>> snd_hda_power_up_pm()? > >> If am not wrong, PM apis exposed either provide RPM_ACTIVE or > >> RPM_SUSPENDED status. Don't see anything which provides info on > >> RPM_SUSPENDING. We might need to exactly know this state to fix this > >> issue. > > Well, maybe my question wasn't clear. What I meant was that your > > change below > > > >> ret = snd_hda_power_up_pm(codec); > >> - if (ret < 0 && pm_runtime_suspended(hda_codec_dev(codec))) > >> + if ((ret < 0 && pm_runtime_suspended(dev)) || > >> + (dev->power.runtime_status == RPM_SUSPENDING)) > >> goto out; > > can be rather like: > > > >> + if (dev->power.runtime_status == RPM_SUSPENDING) > >> + return; > >> ret = snd_hda_power_up_pm(codec); > >> if (ret < 0 && pm_runtime_suspended(hda_codec_dev(codec))) > > so that it skips unneeded power up/down calls. > > > > Basically the state is set at drivers/base/power/runtime.c > > rpm_suspend() just before calling the device's runtime_suspend > > callback. So the state is supposed to be same before and after > > snd_hda_power_up_pm() in that case. > Thanks!, Make sense, will push the updated patch after testing with > latest suggestion. Thanks. Also don't forget to cover a case the test bot complained: the reference to power.runtime_status needs #ifdef CONFIG_PM. Takashi
