Hi Ulf, Am 02.04.2014 13:25, schrieb Ulf Hansson: > On 27 March 2014 16:32, Stefan Wahren <stefan.wahren@xxxxxxxx> 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. >> >> The following patch based on the work of Peter Chen and Otavio Salvador. It >> catches the case that the determined timeout is still 0 and set it's to a >> valid value. >> >> Successful tested on a i.MX28 board. >> >> Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx> >> --- >> drivers/mmc/core/core.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c >> index 098374b..a9cd996 100644 >> --- a/drivers/mmc/core/core.c >> +++ b/drivers/mmc/core/core.c >> @@ -815,6 +815,10 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card) >> data->timeout_ns = limit_us * 1000; >> data->timeout_clks = 0; >> } >> + >> + /* assign limit value if invalid */ >> + if (data->timeout_ns == 0) > Shouldn't you be checking the local variable "timeout_us" instead? you're right. > Or are you saying that tacc_clks is correct for this SD card but not tacc_ns? No, like many other of the fields they are zero (here is a dump with this specific sd card): root@duckbill:/sys/class/block/mmcblk0/device# grep "" * 2>/dev/null cid:0000005553442020000000000000583f csd:00000032535a83bfedb7ffbf1680003f date:08/2005 erase_size:512 fwrev:0x0 hwrev:0x0 manfid:0x000000 name:USD oemid:0x0000 preferred_erase_size:4194304 scr:0225000000000000 serial:0x00000000 type:SD uevent:DRIVER=mmcblk uevent:MMC_TYPE=SD uevent:MMC_NAME=USD uevent:MODALIAS=mmc:block May be this has an influence on your preferred option. Thanks for your feedback. Best regards Stefan Wahren > > We also have MMC_QUIRK_LONG_READ_TIME. Inventing one for WRITE as well > and then add this card for both quirks is another option to solve the > problem. Not sure which one I prefer yet. :-) > > Kind regards > Ulf Hansson > >> + data->timeout_ns = limit_us * 1000; >> } >> >> /* >> -- >> 1.7.10.4 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Software-Entwickler / software developer I2SE GmbH Tel: +49 (0) 341 355667-00 Friedrich-Ebert-Str. 61 Fax: +49 (0) 341 355667-02 04109 Leipzig Germany Web: http://www.i2se.com/ Mail: info@xxxxxxxx VAT No.: DE 811528334 Amtsgericht Leipzig HRB 23784 Geschäftsführer/CEO: Carsten Ziermann *** Diese E-Mail ist allein für den bezeichneten Adressaten bestimmt. Sie kann rechtlich vertrauliche Informationen enthalten. 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