From: ShihPo Hung <shihpo.hung@xxxxxxxxxx> From: Andreas Koop <andreas.koop@xxxxxx> Hello, While using the mmc_spi driver occasionally errors like this popped up: mmcblk0: error -84 transferring data end_request: I/O error, dev mmcblk0, sector 581756 I looked on the Internet for occurences of the same problem and came across a helpful post [1]. It includes source code to reproduce the bug. There is also an analysis about the cause. During transmission data in the supplied buffer is being modified. Thus the previously calculated checksum is not correct anymore. After some digging I found out that device drivers are supposed to report they need stable writes. To fix this I set the appropriate flag at queue initialization if CRC checksumming is enabled for that SPI host. [1] https://groups.google.com/forum/#!msg/sim1/gLlzWeXGFr8/KevXinUXfc8J Signed-off-by: Andreas Koop <andreas.koop@xxxxxx> [shihpo: rebase this on v5.3-rc1] Signed-off-by: ShihPo Hung <shihpo.hung@xxxxxxxxxx> Cc: Andreas Koop <andreas.koop@xxxxxx> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Cc: linux-mmc@xxxxxxxxxxxxxxx Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> --- drivers/mmc/core/queue.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index e327f80..7102e2e 100644 --- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c @@ -10,6 +10,7 @@ #include <linux/kthread.h> #include <linux/scatterlist.h> #include <linux/dma-mapping.h> +#include <linux/backing-dev.h> #include <linux/mmc/card.h> #include <linux/mmc/host.h> @@ -427,6 +428,10 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card) goto free_tag_set; } + if (mmc_host_is_spi(host) && host->use_spi_crc) + mq->queue->backing_dev_info->capabilities |= + BDI_CAP_STABLE_WRITES; + mq->queue->queuedata = mq; blk_queue_rq_timeout(mq->queue, 60 * HZ); -- 2.7.4
