| Message ID | 20210408092559.3824-1-dinghao.liu@zju.edu.cn |
|---|---|
| State | Accepted |
| Commit | a21fbc42807b15b74b0891bd557063e6acf4fcae |
| Headers | show |
| Series | spi: spi-zynqmp-gqspi: Fix runtime PM imbalance in zynqmp_qspi_probe | expand |
Hi Dinghao, On 4/8/21 6:33 PM, Michal Simek wrote: > ++ > > On 4/8/21 11:25 AM, Dinghao Liu wrote: >> When platform_get_irq() fails, a pairing PM usage counter >> increment is needed to keep the counter balanced. It's the >> same for the following error paths. >> >> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> >> --- >> drivers/spi/spi-zynqmp-gqspi.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c >> index c8fa6ee18ae7..95963a2de64a 100644 >> --- a/drivers/spi/spi-zynqmp-gqspi.c >> +++ b/drivers/spi/spi-zynqmp-gqspi.c >> @@ -1197,6 +1197,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev) >> return 0; >> >> clk_dis_all: >> + pm_runtime_get_noresume(&pdev->dev); >> pm_runtime_set_suspended(&pdev->dev); >> pm_runtime_disable(&pdev->dev); >> clk_disable_unprepare(xqspi->refclk); >> The imbalance is because pm_runtime_put_autosuspend is called to make counter to be -1. It looks strange that there is no counter increament op before pm_runtime_put_autosuspend. In my limited understanding, it should look like: ...... pm_runtime_enable pm_runtime_get_sync //increase counter to one to resume device DO OPERATIONS HERE pm_runtime_mark_last_busy pm_runtime_put_autosuspend //decrease counter to zero and trigger suspend return 0; error_path: pm_runtime_put_sync pm_runtime_disable return err; Am I missing something? Thanks, Quanyang
> Hi Dinghao, > > On 4/8/21 6:33 PM, Michal Simek wrote: > > ++ > > > > On 4/8/21 11:25 AM, Dinghao Liu wrote: > >> When platform_get_irq() fails, a pairing PM usage counter > >> increment is needed to keep the counter balanced. It's the > >> same for the following error paths. > >> > >> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > >> --- > >> drivers/spi/spi-zynqmp-gqspi.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c > >> index c8fa6ee18ae7..95963a2de64a 100644 > >> --- a/drivers/spi/spi-zynqmp-gqspi.c > >> +++ b/drivers/spi/spi-zynqmp-gqspi.c > >> @@ -1197,6 +1197,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev) > >> return 0; > >> > >> clk_dis_all: > >> + pm_runtime_get_noresume(&pdev->dev); > >> pm_runtime_set_suspended(&pdev->dev); > >> pm_runtime_disable(&pdev->dev); > >> clk_disable_unprepare(xqspi->refclk); > >> > The imbalance is because pm_runtime_put_autosuspend is called to make > counter to be -1. > > It looks strange that there is no counter increament op before > pm_runtime_put_autosuspend. > > In my limited understanding, it should look like: > > ...... > > pm_runtime_enable > > pm_runtime_get_sync //increase counter to one to resume device > > DO OPERATIONS HERE > > pm_runtime_mark_last_busy > pm_runtime_put_autosuspend //decrease counter to zero and trigger suspend > > return 0; > > error_path: > > pm_runtime_put_sync > > pm_runtime_disable > > return err; > > > Am I missing something? > Thanks for point out this! Usually there is an increment refcount in a _probe function and a decrement refcount in a _remove function. Sometimes the refcount decrement is in the _probe and the increment is in the _remove. But the refcount is balanced in both cases. So I think zynqmp_qspi_remove() needs a refcount increment to fix this bug. Regards, Dinghao
diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c index c8fa6ee18ae7..95963a2de64a 100644 --- a/drivers/spi/spi-zynqmp-gqspi.c +++ b/drivers/spi/spi-zynqmp-gqspi.c @@ -1197,6 +1197,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev) return 0; clk_dis_all: + pm_runtime_get_noresume(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); pm_runtime_disable(&pdev->dev); clk_disable_unprepare(xqspi->refclk);
When platform_get_irq() fails, a pairing PM usage counter increment is needed to keep the counter balanced. It's the same for the following error paths. Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> --- drivers/spi/spi-zynqmp-gqspi.c | 1 + 1 file changed, 1 insertion(+)