Re: [PATCH] [RFC] Revert "mmc: core: Fixup support for writeback-cache for eMMC and SD"

[Marek Vasut <marex@denx.de>]

On 6/16/23 12:33, Ulf Hansson wrote:

Hi,

[...]

>>>>>> I have been trying to follow the progress around this matter. If I
>>>>>> understand correctly we are leaning towards making a card quirk for
>>>>>> this particular SD, to avoid us from turning on and using a broken
>>>>>> cache feature.
>>>>>>
>>>>>> Or what are you thinking?
>>>>>
>>>>> That is probably the simplest option.
>>>>
>>>> Just give me a day or two to test the other newer card.
>>>>
>>>> What would you base that quirk off of ? Date ? We don't know when the
>>>> "fixed" cards started to be produced .
>>>
>>> Right. It seems like the best we can do is to make a quirk for that
>>> particular version of card that you proved to have failed.
>>
>> I just sent a few more data points . It is either date, or C_SIZE, or
>> ERASE_TIMEOUT (if I decode it right). I can also just archive the card,
>> since we have sample size of the defective card equal 1 . It could just
>> be a defective card after all, although the fact that only cache would
>> be defective is unusual.
> 
> I wouldn't mind having a card quirk and to use "date". But it looks
> like it's your call to make. :-)

I sent the quirk patch:

[PATCH] mmc: Add MMC_QUIRK_BROKEN_SD_CACHE for Kingston Canvas Go Plus 
from 11/2019

It seems it is a bit bigger than I though it would originally be.