Re: [PATCH v2] misc: rtsx: Add short delay after exit from ASPM

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

On Fri, May 22, 2020 at 11:18:24AM +0200, Klaus Doth wrote:
> From: Klaus Doth <kdlnx@doth.eu>
> 
> 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@doth.eu>
> ---
>  drivers/misc/cardreader/rtsx_pcr.c | 3 +++
>  1 file changed, 3 insertions(+)

What changed from v1?  Always put that below the --- line like the
documentation says to do so.

> 
> diff --git a/drivers/misc/cardreader/rtsx_pcr.c
> b/drivers/misc/cardreader/rtsx_pcr.c
> index 06038b325b02..3a6a6988cf80 100644
> --- a/drivers/misc/cardreader/rtsx_pcr.c
> +++ b/drivers/misc/cardreader/rtsx_pcr.c
> @@ -141,6 +141,9 @@ static void rtsx_comm_pm_full_on(struct rtsx_pcr *pcr)
>      struct rtsx_cr_option *option = &pcr->option;
>  
>      rtsx_disable_aspm(pcr);
> +   
> +    /* Fixes DMA transfer timeout issue after disabling ASPM on RTS5260 */
> +    msleep(1);
>  
>      if (option->ltr_enabled)
>          rtsx_set_ltr_latency(pcr, option->ltr_active_latency);

All tabs are gone and replaced with spaces, making this impossible to
apply :(

thanks,

greg k-h