On Saturday 12 November 2016 12:58 AM, Tony Lindgren wrote:
> If we return early on pm_runtime_get() error, we need to also call
> pm_runtime_put_noidle() as pointed out in a musb related thread
> by Johan Hovold <johan@xxxxxxxxxx>. This is to keep the PM runtime
> use counts happy.
>
> Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
> Cc: Johan Hovold <johan@xxxxxxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
> drivers/dma/cppi41.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
> --- a/drivers/dma/cppi41.c
> +++ b/drivers/dma/cppi41.c
> @@ -366,8 +366,11 @@ static int cppi41_dma_alloc_chan_resources(struct dma_chan *chan)
> int error;
>
> error = pm_runtime_get_sync(cdd->ddev.dev);
> - if (error < 0)
> + if (error < 0) {
> + pm_runtime_put_noidle(cdd->ddev.dev);
> +
If pm_runtime_get_sync() fails due to callback error, then
rpm_callback() sets dev.power.runtime_error to an error value which gets
cleared by an explicit call to pm_runtime_set_suspended().
This will tell the framework that the status of device is suspended.
Else, the failure will be sticky and on subsequent attempts,
rpm_resume() will keep returning early instead of trying to resume the
device again.
This is as far as I can gather from code. So, I believe the recovery
path should be:
if (error < 0) {
pm_runtime_set_suspended(cdd->ddev.dev);
pm_runtime_put_noidle(cdd->ddev.dev);
...
Thanks,
Sekhar
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