On Thu, Mar 27, 2014 at 12:32 PM, 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. 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. Regards, Fabio Estevam -- 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
