On 18.11.2021 22:28, Takashi Iwai wrote:
On Thu, 18 Nov 2021 21:33:34 +0100, Heiner Kallweit wrote:
I get the following warning caused by 4f66a9ef37d3 ("ALSA: hda: intel: More comprehensive PM runtime setup for controller driver"):
snd_hda_intel 0000:00:1f.3: Unbalanced pm_runtime_enable!
Not sure how this patch was tested because the warning is obvious. The patch doesn't consider what the PCI sub-system does with regard to RPM. Have a look at pci_pm_init().
I'd understand to add the call to pm_runtime_dont_use_autosuspend(), but for all other added calls I see no justification.
If being unsure about when to use which RPM call best involve linux-pm@vger.kernel.org.
Thanks for the notice. It's been through Intel CI and tests on a few local machines, maybe we haven't checked carefully those errors but only concentrated on the other issues, as it seems.
There were two problems: one was the runtime PM being kicked off even during the PCI driver remove call, and another was the proper runtime PM setup after re-binding.
Having a look at the commit message of "ALSA: hda: fix general protection fault in azx_runtime_idle" the following sounds weird:
- pci-driver.c:pm_runtime_put_sync() leads to a call to rpm_idle() which again calls azx_runtime_idle()
rpm_idle() is only called if usage_count is 1 when entering pm_runtime_put_sync. And this should not be the case. pm_runtime_get_sync() increments the usage counter before remove() is called, and remove() should also increment the usage counter. This doesn't seem to happen. Maybe for whatever reason pm_runtime_get_noresume() isn't called in azx_free(), or azx_free() isn't called from remove(). I think you should trace the call chain from the PCI core calling remove() to pm_runtime_get_noresume() getting called or not.
For avoiding the former, only the pm_runtime_forbid() (and maybe pm_runtime_dont_use_autosuspend(), too) would suffice? Also, for PCI device, no need for pm_runtime_set_supended() at remove, right?
thanks,
Takashi