On 2020/4/14 下午6:27, Takashi Iwai wrote:
On Tue, 14 Apr 2020 12:14:05 +0200, Hui Wang wrote:
Before the pci_driver->probe() is called, the pci subsystem calls runtime_forbib() and runtime_get_sync() on this pci dev, so only call runtime_put_autosuspend() is not enough to enable the runtime_pm on this device.
For controllers with vgaswitcheroo feature, the pci/quirks.c will call runtime_allow() for this dev, then the controllers could enter rt_idle/suspend/resume, but for non-vgaswitcheroo controllers like Intel hda controllers, the runtime_pm is not enabled even it calls put_autosuspend(). Need to call runtime_allow() for those controllers in the hda driver.
Signed-off-by: Hui Wang hui.wang@canonical.com
Was this behavior changed from the earlier kernels? I thought this was left untouched because it's supposed to be set via udev rules or such.
Oh, I don't know that, according to my test with ubuntu rootfs, the runtime pm is not enabled on Intel's hda controllers. But with the sof driver, the controller driver calls runtime_allow() (soc/sof/sof-pci-dev.c), so I sent this patch.
Regards,
Hui.
OTOH, enabling the runtime PM is almost mandatory for modern systems, and I'm fine to apply this kind of forcible enablement.
thanks,
Takashi
sound/pci/hda/hda_intel.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index 8519051a426e..779705bef88b 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -2356,6 +2356,8 @@ static int azx_probe_continue(struct azx *chip)
if (azx_has_pm_runtime(chip)) { pm_runtime_use_autosuspend(&pci->dev);
if (!use_vga_switcheroo(chip))pm_runtime_allow(&pci->dev);-- 2.17.1