On Thu, 16 Oct 2008 16:26:55 +0300
Adrian Hunter <ext-adrian.hunter@xxxxxxxxx> wrote:
In particular, if the card gets an ECC error it will
timeout, in which case it is much more helpful to see
an ECC error rather than a timeout error.
Signed-off-by: Adrian Hunter <ext-adrian.hunter@xxxxxxxxx>
---
Woo. I think you're the first I've seen that has been able to trigger
an actual card error. :)
As for the patch, I like the idea but I'm not entirely satisfied with
the implementation.
+static void print_data_error(struct mmc_blk_request *brq, struct mmc_card *card,
+ struct request *req)
+{
+ struct mmc_command cmd;
+ char *emsg;
+ u32 status;
+ int status_err = 0;
+
+ if (brq->data.error != -ETIMEDOUT || mmc_host_is_spi(card->host))
+ goto out_print;
+
The error codes are more of a hint than anything else, so you should
check the status for all non-zero codes. You should also not just check
data.error, but all of them.
And why exclude spi?
+ if (brq->mrq.stop)
+ /* 'Stop' response contains card status */
+ status = brq->mrq.stop->resp[0];
+ else {
+ cmd.opcode = MMC_SEND_STATUS;
+ cmd.arg = card->rca << 16;
+ cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+ status_err = mmc_wait_for_cmd(card->host, &cmd, 0);
+ if (status_err)
+ goto out_print;
+ status = cmd.resp[0];
+ }
Errors can occur on writes as well, so I suggest accumulating the
status bits instead of trying to get the entire set in one go. I.e.:
status = 0;
if (mrq.stop)
status |= mrq.stop.resp[0];
while (card not ready)
status |= send_status();
IOW, you should do this in the main handler (that already has the
status loop for writes).
+
+ emsg = (status & R1_CARD_ECC_FAILED) ? "ECC" : "I/O";
+
There are also some other error codes that can be of interest.
"Internal controller error" for example.
(it's probably also better to state "Unknown" error and not "I/O" for
the fallback)
@@ -281,10 +322,8 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
req->rq_disk->disk_name, brq.cmd.error);
}
- if (brq.data.error) {
- printk(KERN_ERR "%s: error %d transferring data\n",
- req->rq_disk->disk_name, brq.data.error);
- }
+ if (brq.data.error)
+ print_data_error(&brq, card, req);
Please keep the old message and add this as a new extra piece of
information. It is helpful for debugging to see both what the driver
and the card reported.