Re: [PATCH] mmc: core: Use maximum timeout values in case TACC field is zero

[Stefan Wahren <stefan.wahren@i2se.com>]

Am 27.03.2014 16:41, schrieb Fabio Estevam:
> On Thu, Mar 27, 2014 at 12:32 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
>> When plugging a specific micro SD card at MMC socket of a custom i.MX28 board,
>> we get the following kernel warning:
>>
>> WARNING: CPU: 0 PID: 30 at drivers/mmc/host/mxs-mmc.c:342 mxs_mmc_start_cmd+0x34c/0x378()
>> Modules linked in:
>> CPU: 0 PID: 30 Comm: kworker/u2:1 Not tainted 3.14.0-rc5 #8
>> Workqueue: kmmcd mmc_rescan
>> [<c0015420>] (unwind_backtrace) from [<c0012cb0>] (show_stack+0x10/0x14)
>> [<c0012cb0>] (show_stack) from [<c001daf8>] (warn_slowpath_common+0x6c/0x8c)
>> [<c001daf8>] (warn_slowpath_common) from [<c001db34>] (warn_slowpath_null+0x1c/0x24)
>> [<c001db34>] (warn_slowpath_null) from [<c0349478>] (mxs_mmc_start_cmd+0x34c/0x378)
>> [<c0349478>] (mxs_mmc_start_cmd) from [<c0338fa0>] (mmc_start_request+0xc4/0xf4)
>> [<c0338fa0>] (mmc_start_request) from [<c03390b4>] (mmc_wait_for_req+0x50/0x164)
>> [<c03390b4>] (mmc_wait_for_req) from [<c03405b8>] (mmc_app_send_scr+0x158/0x1c8)
>> [<c03405b8>] (mmc_app_send_scr) from [<c033ee1c>] (mmc_sd_setup_card+0x80/0x3c8)
>> [<c033ee1c>] (mmc_sd_setup_card) from [<c033f788>] (mmc_sd_init_card+0x124/0x66c)
>> [<c033f788>] (mmc_sd_init_card) from [<c033fd7c>] (mmc_attach_sd+0xac/0x174)
>> [<c033fd7c>] (mmc_attach_sd) from [<c033a658>] (mmc_rescan+0x25c/0x2d8)
>> [<c033a658>] (mmc_rescan) from [<c003597c>] (process_one_work+0x1b4/0x4ec)
>> [<c003597c>] (process_one_work) from [<c0035de4>] (worker_thread+0x130/0x464)
>> [<c0035de4>] (worker_thread) from [<c003c824>] (kthread+0xb4/0xd0)
>> [<c003c824>] (kthread) from [<c000f420>] (ret_from_fork+0x14/0x34)
>>
>> The error is due to an invalid value in CSD register of a specific 2GB micro
>> SD card. The CSD version of this card is 1.0 but the TACC field has the invalid
>> value 0. Since the kernel is making use of this TACC field to calculate the
>> SD card timeout, an invalid value 0 leads to a warning at mxs_ns_to_ssp_ticks()
>> and later the following misleading error messages appears in a loop:
>>
>> mxs-mmc 80010000.ssp: card claims to support voltages below defined range
>> mxs-mmc 80010000.ssp: no support for card's volts
>> mmc0: error -22 whilst initialising MMC card
>>
>> This error is only found on this 2GB SD card on mxs platform.
>> On x86 this card works without any problems.
> Thanks for the patch, Stefan.
>
>> The following patch based on the work of Peter Chen and Otavio Salvador. It
> It was Peter Chan, not Peter Chen.

Oops, i will fix that but i don't have his mail address.

Beside that, are there any other opinions about this patch?

>
> Regards,
>
> Fabio Estevam

Best regards,

Stefan Wahren