| Message ID | 20221015004934.3930651-1-swboyd@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [RESEND,1/2] soc: qcom: cmd-db: Mark device as having no PM support | expand |
On Fri, 14 Oct 2022 17:49:33 -0700, Stephen Boyd wrote: > This driver purely exposes information from memory to the kernel. Let's > mark it as not having any device PM functionality, so that during > suspend we skip even trying to call a suspend function on this device. > This clears up suspend logs more than anything else, but it also shaves > a few cycles off suspend. > > > [...] Applied, thanks! [1/2] soc: qcom: cmd-db: Mark device as having no PM support commit: 5f7e2cb56af6800a4158514cc27921141e67ae19 [2/2] soc: qcom: stats: Mark device as having no PM support commit: 367b9c70e9b25fe9ad5346b0f3544682d8b112b9 Best regards,
Hi Stephen, On Fri, Oct 14, 2022 at 05:49:33PM -0700, Stephen Boyd wrote: > This driver purely exposes information from memory to the kernel. Let's > mark it as not having any device PM functionality, so that during > suspend we skip even trying to call a suspend function on this device. > This clears up suspend logs more than anything else, but it also shaves > a few cycles off suspend. > > Cc: Konrad Dybcio <konrad.dybcio@somainline.org> > Signed-off-by: Stephen Boyd <swboyd@chromium.org> > --- > > Resend to fix Bjorn's email. > > drivers/soc/qcom/cmd-db.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c > index 629a7188b576..33856abd560c 100644 > --- a/drivers/soc/qcom/cmd-db.c > +++ b/drivers/soc/qcom/cmd-db.c > @@ -338,6 +338,8 @@ static int cmd_db_dev_probe(struct platform_device *pdev) > > debugfs_create_file("cmd-db", 0400, NULL, NULL, &cmd_db_debugfs_ops); > > + device_set_pm_not_required(&pdev->dev); > + > return 0; > } > > Sorry for asking this question here, thought it would be easy for you to get the context. I was recently reading this driver and learned about device_set_pm_not_required() API. However, it is not clear how this is working in practice? The driver is calling device_set_pm_not_required() in probe(), however all the checks for device_pm_not_required() happen before probe() is called. For ex: dpm_sysfs_add() and device_pm_add() both happens before probe(). I was expecting not to see /sys/bus/platform/devices/XXXXXX.aop-cmd-db/power directory but it is still present. Also, I believe once driver set this flag, the device clean up might not remove sysfs entries as we have device_pm_not_required() checks active by that time. Would it make sense to add code after probe() and take some action if device_pm_not_required() returns true? Thanks, Pavan
diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c index 629a7188b576..33856abd560c 100644 --- a/drivers/soc/qcom/cmd-db.c +++ b/drivers/soc/qcom/cmd-db.c @@ -338,6 +338,8 @@ static int cmd_db_dev_probe(struct platform_device *pdev) debugfs_create_file("cmd-db", 0400, NULL, NULL, &cmd_db_debugfs_ops); + device_set_pm_not_required(&pdev->dev); + return 0; }
This driver purely exposes information from memory to the kernel. Let's mark it as not having any device PM functionality, so that during suspend we skip even trying to call a suspend function on this device. This clears up suspend logs more than anything else, but it also shaves a few cycles off suspend. Cc: Konrad Dybcio <konrad.dybcio@somainline.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> --- Resend to fix Bjorn's email. drivers/soc/qcom/cmd-db.c | 2 ++ 1 file changed, 2 insertions(+) base-commit: 4fe89d07dcc2804c8b562f6c7896a45643d34b2f