There is a race condition between resetting the SDHCI controller and disconnecting the card. For example: 0) Card is connected and transferring data 1) mmc_sd_reset is called to reset the controller due to a data error 2) sdhci_set_ios calls sdhci_do_reset 3) SOFT_RESET_ALL is toggled which clears the IRQs the controller has configured. 4) Wait for SOFT_RESET_ALL to clear 5) CD logic notices card is gone and CARD_PRESENT goes low, but since the IRQs are not configured a CARD_REMOVED interrupt is never raised. 6) IRQs are enabled again 7) mmc layer never notices the device is disconnected. The SDHCI layer will keep returning -ENOMEDIUM. This results in a card that is always present and not functional. Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx> --- You can see an example of the following two patches here: https://privatebin.net/?b0f5953716d34ca6#C699bCBQ99NdvspfDW7CMucT8CJG4DgL+yUNPyepDCo= Line 8213: EILSEQ Line 8235: SDHC is hard reset Line 8240: Controller completes reset and card is no longer present Line 8379: mmc_sd_reset notices card is missing and issues a card_event and schedules a detect change. Line 8402: Don't init the card since it's already gone. Line 8717: Marks card as removed Line 8820: mmc_sd_remove removes the block device I am running into a kernel panic. A task gets stuck for more than 120 seconds. I keep seeing blkdev_close in the stack trace, so maybe I'm not calling something correctly? Here is the panic: https://privatebin.net/?8ec48c1547d19975#dq/h189w5jmTlbMKKAwZjUr4bhm7Q2AgvGdRqc5BxAc= I sometimes see the following: [ 547.943974] udevd[144]: seq 2350 '/devices/pci0000:00/0000:00:14.7/mmc_host/mmc0/mmc0:0001/block/mmcblk0/mmcblk0p1' is taking a long time I was getting the kernel panic on a 4.14 kernel: https://chromium.googlesource.com/chromiumos/third_party/kernel/+/f3dc032faf4d074f20ada437e2d081a28ac699da/drivers/mmc/host So I'm guessing I'm missing an upstream fix. Do the patches look correct or am I doing something that would cause a kernel panic? I have a DUT setup with a GPIO I can use to toggle the CD pin. I ran a test where I connect and then randomly, between 0s - 1s disconnect the card. This got over 20k iterations before the panic. Though when I do it manually and stop for 2 minutes the panic happens. Any help would be appreciated. Thanks, Raul drivers/mmc/core/sd.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index 265e1aeeb9d8..9206c4297d66 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -1242,7 +1242,27 @@ static int mmc_sd_runtime_resume(struct mmc_host *host) static int mmc_sd_hw_reset(struct mmc_host *host) { + int present; mmc_power_cycle(host, host->card->ocr); + + present = host->ops->get_cd(host); + + /* The card status could have changed while resetting. */ + if ((mmc_card_removed(host->card) && present) || + (!mmc_card_removed(host->card) && !present)) { + pr_info("%s: card status changed during reset\n", + mmc_hostname(host)); + host->ops->card_event(host); + mmc_detect_change(host, 0); + } + + /* Don't perform unnecessary transactions if the card is missing. */ + if (!present) { + pr_info("%s: card was removed during reset\n", + mmc_hostname(host)); + return -ENOMEDIUM; + } + return mmc_sd_init_card(host, host->card->ocr, host->card); } -- 2.21.0.593.g511ec345e18-goog
