On Tue, 14 Apr 2020 14:40:35 +0200, Takashi Iwai wrote:
On Tue, 14 Apr 2020 14:35:50 +0200, Hui Wang wrote:
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.
OK, I just watned to know the situation. So it's no regression but rather to align the behavior among drivers, and that's fine. Let's take the patch, then.
On the second thought, we can drop the vga_switcheroo check and always allow it? We do want to enable in anyway, and calling it twice should be fine.
thanks,
Takashi
thanks,
Takashi
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