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Message-ID: <20071027140017.41e9d67f@poseidon.drzeus.cx>
Date: Sat, 27 Oct 2007 14:00:17 +0200
From: Pierre Ossman <drzeus-list@...eus.cx>
To: Roopesh <roopesh@...erspace.org>
Cc: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: MMC: CRC Errors with 2GB cards
Hi Roopesh,
I'm terribly sorry I haven't replied sooner. I put your message on my todo list, figuring I could get to it within a day or two, but as you noticed, that didn't quite happen. :/
On Fri, 19 Oct 2007 12:17:00 -0400
Roopesh <roopesh@...erspace.org> wrote:
> Hi,
>
> I am seeing a lot of CRC errors happening with CMD25 on a couple
> of Transcend 2GB cards (specifiation version 1.1). However, if
> I apply the following patch, I see no errors being reported
>
Ok, so the card is mishandling the state bits a bit. We should be able to work around that.
> @@ -310,8 +311,8 @@
> req->rq_disk->disk_name, err);
> goto cmd_err;
> }
> - } while (!(cmd.resp[0] & R1_READY_FOR_DATA));
> -
> + } while (!(R1_CURRENT_STATE(cmd.resp[0]) == 4));
> +
> #if 0
This might trade us one problem for another. Could you try the following:
} while (!(cmd.resp[0] & R1_READY_FOR_DATA) || (R1_CURRENT_STATE(cmd.resp[0]) == 7));
This should also work for cards that mishandle the state field, and if the card jumps to
some odd state for some reason.
>
> I am just wondering if I have set of broken cards. Any pointers
> in this regard?
>
You do. But don't be too alarmed, that is unfortunately the norm. :/
Rgds
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
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