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, Takashi
