Date: Fri, 9 Jul 2010 16:54:15 GMT From: Greg Ansley <gja@ansley.com> To: freebsd-gnats-submit@FreeBSD.org Subject: arm/148474: MMC timeout too short durring enumeration of cards. Message-ID: <201007091654.o69GsF1n032013@www.freebsd.org> Resent-Message-ID: <201007091700.o69H0E0d082975@freefall.freebsd.org>
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>Number: 148474
>Category: arm
>Synopsis: MMC timeout too short durring enumeration of cards.
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-arm
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jul 09 17:00:14 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator: Greg Ansley
>Release: 8-stabe & 9-current
>Organization:
Ansley & Associates, Inc.
>Environment:
>Description:
Large SD cards take much longer to come out of the power-up state than earlier smaller cards.
Current command loop terminates after 100 attempts waiting for a card to become ready. A 1G card currently takes 241 iterations to become ready on a 400Mhz AT91SAM9G20. A 8G card was took 721.
SD card spec does not specify a maximum wait time.
The patch bumps the loop count to for 100 to 5000. Note that this does not affect the no-card or error condition timings.
>How-To-Repeat:
Boot system with SD card present. Large cards will not be found. Small cards work fine.
>Fix:
Patch attached with submission follows:
Index: mmc.c
===================================================================
RCS file: /usr/home/ncvs/src/sys/dev/mmc/mmc.c,v
retrieving revision 1.38
diff -r1.38 mmc.c
451c451
< for (i = 0; i < 100; i++) {
---
> for (i = 0; i < 5000; i++) {
478c478
< for (i = 0; i < 100; i++) {
---
> for (i = 0; i < 5000; i++) {
>Release-Note:
>Audit-Trail:
>Unformatted:
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