Re: [PATCH] mmc: core: Wait for command setting 'Power Off Notification' bit to complete

[Andrey Skvortsov <andrej.skvortzov@gmail.com>]

Hi, Ulf

On 22-01-18 19:48, Ulf Hansson wrote:
> On Sat, 15 Jan 2022 at 13:15, Andrey Skvortsov
> <andrej.skvortzov@gmail.com> wrote:
> >
> > SD card is allowed to signal busy on DAT0 up to 1s after the
> > CMD49. According to SD spec (version 6.0 section 5.8.1.3) first host
> > waits until busy of CMD49 is released and only then polls Power
> > Management Status register up to 1s until the card indicates ready to
> > power off.
> >
> > Without waiting for busy before polling status register sometimes card
> > becomes unresponsive and system fails to suspend:
> >
> >   [  205.907459] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
> >   [  206.421274] sunxi-mmc 1c0f000.mmc: data error, sending stop command
> >   [  206.421321] sunxi-mmc 1c0f000.mmc: send stop command failed
> >   [  206.421347] mmc0: error -110 reading status reg of PM func
> >   [  206.421366] PM: dpm_run_callback(): mmc_bus_suspend+0x0/0x74 returns -110
> >   [  206.421402] mmcblk mmc0:aaaa: PM: failed to suspend async: error -110
> >   [  206.437064] PM: Some devices failed to suspend, or early wake event detected
> 
> Thanks for your patch!
> 
> I recall I was hesitating on adding another busy completion check for
> this, but thought polling the status register for the power management
> function should be sufficient.
> 
> >
> > Tested with Sandisk Extreme PRO A2 64GB on Allwinner A64 system.
> 
> I will give this patch a try too, to make sure it still works on my
> side. Assuming that works fine, I will queue this up for fixes and by
> adding a fixes/stable tag.

Thank you! More testing would be certainly great, because only one of my SD-cards
supports "Power Notification".

-- 
Best regards,
Andrey Skvortsov