On Fri, May 22, 2020 at 10:23 AM Klaus Doth <kdlnx@xxxxxxx> wrote:
>
> From: Klaus Doth <kdlnx@xxxxxxx>
>
> DMA transfers to and from the SD card stall for 10 seconds and run into
> timeout on RTS5260 card readers after ASPM was enabled.
>
> Adding a short msleep after disabling ASPM fixes the issue on several
> Dell Precision 7530/7540 systems I tested.
>
> This function is only called when waking up after the chip went into
> power-save after not transferring data for a few seconds. The added
> msleep does therefore not change anything in data transfer speed or
> induce any excessive waiting while data transfers are running, or the
> chip is sleeping. Only the transition from sleep to active is affected.
>
> Signed-off-by: Klaus Doth <kdlnx@xxxxxxx>
> ---
> drivers/misc/cardreader/rtsx_pcr.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/misc/cardreader/rtsx_pcr.c
> b/drivers/misc/cardreader/rtsx_pcr.c
> index 06038b325b02..8b0799cd88c2 100644
> --- a/drivers/misc/cardreader/rtsx_pcr.c
> +++ b/drivers/misc/cardreader/rtsx_pcr.c
> @@ -141,6 +141,7 @@ static void rtsx_comm_pm_full_on(struct rtsx_pcr *pcr)
> struct rtsx_cr_option *option = &pcr->option;
>
> rtsx_disable_aspm(pcr);
> + msleep(1);
Your patch looks fine to me, but I think you should put a short version
of that the changelog text into a code comment next to the msleep().
Arnd
