From: Chris Ball <cjb@laptop.org>
To: elad.yi@gmail.com
Cc: linux-mmc@vger.kernel.org, Philip Rakity <prakity@nvidia.com>
Subject: When bus width detection procedure takes place, kernel cannot lock on correct bus width
Date: Sun, 17 Mar 2013 08:07:20 -0400 [thread overview]
Message-ID: <87ip4qdybr.fsf@octavius.laptop.org> (raw)
Hi Elad, I'm forwarding your bug report to the linux-mmc@ list.
- Chris.
I've been working on a bringup of an new board in Harmonic Inc.
This board uses Sandisk iNand eMMC flash.
I've noticed that the mmc driver keeps detecting 1 bit width although HW
supports 4 bit, looked into it, and found the problem. In line 571 at mmc.c:
There is:
/* only compare read only fields */
err = !((card->ext_csd.raw_partition_support ==
bw_ext_csd[EXT_CSD_PARTITION_SUPPORT]) &&
(card->ext_csd.raw_erased_mem_count ==
bw_ext_csd[EXT_CSD_ERASED_MEM_CONT]) &&
(card->ext_csd.rev ==
bw_ext_csd[EXT_CSD_REV]) &&
(card->ext_csd.raw_ext_csd_structure ==
...
The problem is that raw_partition_support is not the same when setting width of
4 bits instead of 1 bit, and shouldn't be compared at all although it is read
only.
this should be changed to:
/* only compare read only fields */
err = !((card->ext_csd.raw_erased_mem_count ==
bw_ext_csd[EXT_CSD_ERASED_MEM_CONT]) &&
(card->ext_csd.rev ==
bw_ext_csd[EXT_CSD_REV]) &&
(card->ext_csd.raw_ext_csd_structure ==
...
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child
next reply other threads:[~2013-03-17 12:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-17 12:07 Chris Ball [this message]
2013-03-22 17:06 ` When bus width detection procedure takes place, kernel cannot lock on correct bus width Chris Ball
2013-03-22 18:56 ` Philip Rakity
2013-03-26 15:54 ` Philip Rakity
2013-04-04 19:37 ` Chris Ball
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