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

[Klaus Doth <kdlnx@doth.eu>]

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