Hi Doug, Great..i have found the problem like this. I will check your patch..and share the result. Best Regards, Jaehoon Chung On 03/16/2013 06:29 AM, Doug Anderson wrote: > On a flaky piece of hardware that seems good at generating CRC errors, > we have found that often times the CRC errors don't get reported > properly when using CONFIG_MMC_DW_IDMAC (they get reported OK when > using pio). > > The flow that happens is: > 1. dw_mci_interrupt() fires and status=80b8, pending=8088 so that > we hit (pending & DW_MCI_DATA_ERROR_FLAGS). We store 8088 in > data_status and set EVENT_DATA_ERROR in host->pending_events > 2. We schedule the tasklet and it runs. > 3. We're in STATE_SENDING_DATA in the tasklet and see > EVENT_DATA_ERROR so we dw_mci_stop_dma(). > 4. dw_mci_stop_dma() calls dw_mci_idmac_stop_dma() and > dw_mci_dma_cleanup(). These stop dma but _don't_ set > EVENT_XFER_COMPLETE (since we're host->using_dma). > 5. data->stop is NULL so we don't send a stop command. > 6. We move onto STATE_DATA_ERROR and loop again in the tasklet. > 7. We hit STATE_DATA_ERROR but the transfer isn't done, so the tasklet > stops. > > We never seem to get any additional DMA interrupts that cause > EVENT_XFER_COMPLETE and restart the tasklet so we just hang. That > doesn't seem surprising given that we've stopped DMA. > > We did put a print at the end of dw_mci_interrupt() to show the result > of the "mci_readl(host, IDSTS)" and saw 0xa000 in the case of the > above CRC error. > > A proposed fix for this is to ignore (but still clear) the > EVENT_XFER_COMPLETE in STATE_DATA_ERROR in the tasklet. > > Reported-by: Bing Zhao <bzhao@xxxxxxxxxxx> > Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx> > --- > drivers/mmc/host/dw_mmc.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 9834221..696b3bb 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1137,10 +1137,7 @@ static void dw_mci_tasklet_func(unsigned long priv) > goto unlock; > > case STATE_DATA_ERROR: > - if (!test_and_clear_bit(EVENT_XFER_COMPLETE, > - &host->pending_events)) > - break; > - > + clear_bit(EVENT_XFER_COMPLETE, &host->pending_events); > state = STATE_DATA_BUSY; > break; > } > -- 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
