Re: [PATCH 1/1] mmc: Some microSD cards are not recognized byPCIxx12 SDA controller

From: Pierre Ossman
Date: Sun Apr 05 2009 - 14:34:14 EST


On Thu, 26 Mar 2009 17:37:10 +0100
Josà MarÃÂa FernÃndez GonzÃlez <josemariafg@xxxxxxxxx> wrote:

> Pierre Ossman wrote:
> > On Wed, 25 Mar 2009 09:00:56 +0100
> > Josà MarÃÂa FernÃndez GonzÃlez <josemariafg@xxxxxxxxx> wrote:
> >
> >> As I'm going to install 2.6.29 today, I can test the patch with it and HZ=100.
> >
> > Please do. And try to determine where it breaks. I'd prefer if we don't
> > need to increase this yet again in a month because we were relying on
> > some scheduling latencies. :)
> >
> > Rgds
>
> I have been testing the patch with kernel 2.6.29 and a couple of cards (the Transcend 2GB microSD and a EZ Memory 8GB SDHC) in a few cases:
>
> * HZ=300 + tickless + desktop preemption
> * HZ=100 + tickless + desktop preemption
> * HZ=100 + desktop preemption
> * HZ=100 + low latency desktop preemption
> * HZ=1000 + tickless + desktop preemption
>
> and it worked with no problem. I don't know if I have forgotten any obvious corner case. Perhaps I should have tested with no preemption...
>

All of them will result in a sleep though. Preferably, I'd like to now
the minimum delay you need to get things working. Change from
mmc_delay() to mdelay() to make sure there aren't any sleeps (which
generally take quite some time to complete).

Rgds
--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org

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