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
--- linux-2.6.22/drivers/mmc/card/block.c 2007-09-27 14:59:44.000000000 +0530
+++ linux-tao/drivers/mmc/card/block.c 2007-10-19 20:53:52.000000000 +0530
@@ -298,6 +298,7 @@
}
if (rq_data_dir(req) != READ) {
+ /* Wait for the card to to be in transfer state*/
do {
int err;
@@ -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
if (cmd.resp[0] & ~0x00000900)
printk(KERN_ERR "%s: status = %08x\n",
I noticed that at times the card is not actually in transfer
state when it recieves the second consecutive
MULTIPLE_BLOCK_WRITE cmd. As per the simplified specification
available, all class 4 commands including CMD25 can be issued
only in tra state, though its also specified that READY_FOR_DATA
indicates whether the card can accept new data.
I am just wondering if I have set of broken cards. Any pointers
in this regard?
Thanks and Regards,
Roopesh.
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 <[email protected]> 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
Hi Pierrie,
Thanks for writing back.
: > - } 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. :/
:
I have purchased 4 Transcend cards, and all of them behave the
same way. Just wondering why others dont have this problem, and
why such a fix hasn't made it to main tree yet.
I have tried the fix, and it works fine. Thanks.
Roopesh.
On Mon, 29 Oct 2007 05:50:15 -0400
Roopesh <[email protected]> wrote:
>
> I have purchased 4 Transcend cards, and all of them behave the
> same way. Just wondering why others dont have this problem, and
> why such a fix hasn't made it to main tree yet.
>
Odd. I have a whole bunch of transcend cards, and I've never gotten this problem. Perhaps yours are rather recent?
> I have tried the fix, and it works fine. Thanks.
>
Great. I'll queue it up for -mm for some more testing, after which it will get merged.
Rgds
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org
:---------- Original Message ----------
:From: Pierre Ossman [[email protected]]
:Sent: Wed, Oct 31, 2007 at 03:55:58PM EDT
:
: Odd. I have a whole bunch of transcend cards, and I've
: never gotten this problem. Perhaps yours are rather recent?
:
Though these cards were purchased only in last month, the
manufactring date (in cid) is shown to be 3-2007. Here are the
entire CID fields:
manfid:28, product_name:SDC , serial=5332, oemid=21334,
month-year=3-2007, hw-fw_rev=1-0
/ # cat /sys/bus/mmc/devices/mmc0\:b368/cid
1c5356534443202010000014d400737d
Thanks and Regards,
Roopesh Keeppattu.