On Monday 14 February 2011, Dong, Chuanxiao wrote:
> When I do trim with a 32GB eMMC card in my platform, sometimes I can get the
> 10s
> timeout errors but sometimes not. I am not much clear about the "discarding
> partial
> AU will take a lot longer". If this action is hide for driver, then I think
> from
> driver side, the UINT_MAX value for max_discard_sectors will be OK. But if
> this action
> sometimes need driver to wait for some hardware interrupt, then I think the
> UINT_MAX
> value is not preferred.
>
> Arnd, have any suggestion of dealing this? What I thought is using other value
> instead of using UINT_MAX.
I'm not too familiar with the eMMC spec, but it should have a way to calculate
a maximum trim timeout like SD 3.0 does for AU erases. When I've seen the
timeouts
with SDHCI (missing your patch), it was always a bug in the driver, and the
erase was already completed before the driver even started waiting for the
interrupt.
10 seconds still sounds like a reasonable timeout, and we should probably
not issue any requests that might take longer than that, so I think the
interesting question is how to determine a good value for pref_erase,
so we can still take your patch.
Arnd
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