[PATCH] mmc: dw_mmc: fix falling from idmac to PIO mode when dw_mci_reset occurs

[Ulf Hansson]

On 15 March 2018 at 14:18, Evgeniy Didin <Evgeniy.Didin at synopsys.com> wrote:
> Hello Ulf,
>
> On Thu, 2018-03-15 at 10:57 +0100, Ulf Hansson wrote:
>> On 14 March 2018 at 20:30, Evgeniy Didin <Evgeniy.Didin at synopsys.com> wrote:
>> > It was found that in IDMAC mode after soft-reset driver switches
>> > to PIO mode.
>> >
>> > That's what happens in case of DTO timeout overflow calculation failure:
>> > 1. soft-reset is called
>> > 2. driver restarts dma
>> > 3. descriptors states are checked, one of descriptor is owned by the IDMAC.
>> > 4. driver can't use DMA and then switches to PIO mode.
>> >
>> > Failure was already fixed in:
>> > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dmmc_msg48125.html&d=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=vQk-RIbjwN0zvlwiMSpq3LYUTNf7Gqc4ujhosYI
>> > TtAw&m=6rPWpKUYQD3kY-2OEikJUWyEJvwKJljWHFC8rd2TCak&s=JjX0Dx8-eSyW2cATMsnG1eAzrKgoDkS1bcS5XYrVtlE&e=.
>>
>> Evgeniy,
>>
>> It seems like I should squash this fix into the above commit? Makes sense?
> IMHO it is not a good idea, because this fix is orthogonal to the above commit.
> Debugging drto overflow issue we found this strange behavior.

Okay! Thanks for clarifying.

> This might be general issue of soft-reset. So I think this should be separate patch.
> Also if these patches are independent, it will be easier to backport them.

Should I add a stable tag then?

[...]

Kind regards
Uffe