Re: 4.13 on thinkpad x220: oops when writing to SD card

[Linus Walleij]

On Thu, Sep 7, 2017 at 9:18 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:

> Even if this fixes the problem it seems like we are papering over the
> real issue, which earlier fixes also did during the release cycle for
> v4.13.

I think this is the real solution to the issue.

>> Another unrelated issue with mmc_init_request() is that mmc_exit_request()
>> is not called if mmc_init_request() fails, which means mmc_init_request()
>> must free anything it allocates when it fails.
>
> Yes, the situations it's just too fragile. We need to fix the behavior
> properly, although I haven't myself been able to investigate exactly
> how yet.
>
> Adding, Linus, perhaps he has some ideas.

Maybe we should simply bite the bullet and do what was suggested
by another contributor when I refactored the bounce buffer handling:
simply delete the bounce buffer code and let any remaining (few?)
legacy devices suffer a bit (performancewise) at the gain of way
simpler code?

I am a bit hesitant about that because Pierre Ossman said it was
actually a big win on the SDHC hosts that made use of it at one
point.

Yours,
Linus Walleij