Re: Possible bug in drivers/misc/cardreader/rtsx_pcr.c

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, May 21, 2020 at 01:50:02PM +0200, Klaus Doth wrote:
> On 5/21/20 10:52 AM, Greg Kroah-Hartman wrote:
> > On Tue, May 19, 2020 at 07:04:06PM +0200, Klaus Doth wrote:
> >> Hi,
> >>
> >>
> >> As per the info from kernelnewbies IRC, I'm sending this also to the PCI
> >> list.
> > <snip>
> >
> > Can you submit a proposed patch in a format that it can be tested and
> > possibly submitted in so that we can review this easier?
> >
> > Also try cc:ing the author of changes in that code, Rui Feng
> > <rui_feng@realsil.com.cn>, as well, as they are the best one to review
> > and comment on your issue.
> >
> > thanks,
> >
> > greg k-h
> 
> 
> 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
> powersave 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 transistion from sleep to active is affected.
> 
> 
> Signed-off-by: Klaus Doth <kdlnx@doth.eu>
> 
> ---
>  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);
>  
>      if (option->ltr_enabled)
>          rtsx_set_ltr_latency(pcr, option->ltr_active_latency);
> -- 
> 2.26.2

Looks sane, can you resend it in a format I can apply it in (i.e. as a
stand-alone patch with a correct subject line?)

thanks,

greg k-h