On 02/28/2016 09:32 PM, Yaniv Gardi wrote: > Some vendor's UFS device sends back to back NACs for the DL data frames > causing the host controller to raise the DFES error status. Sometimes > such UFS devices send back to back NAC without waiting for new > retransmitted DL frame from the host and in such cases it might be > possible the Host UniPro goes into bad state without raising the DFES > error interrupt. If this happens then all the pending commands would > timeout only after respective SW command (which is generally too > large). > > This change workarounds such device behaviour like this: > - As soon as SW sees the DL NAC error, it would schedule the error > handler > - Error handler would sleep for 50ms to see if there any fatal errors > raised by UFS controller. > - If there are fatal errors then SW does normal error recovery. > - If there are no fatal errors then SW sends the NOP command to > device to check if link is alive. > - If NOP command times out, SW does normal error recovery > - If NOP command succeed, skip the error handling. > > If DL NAC error is seen multiple times with some vendor's UFS devices > then enable this quirk to initiate quick error recovery and also > silence related error logs to reduce spamming of kernel logs. > > Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> > Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx> > > --- > drivers/scsi/ufs/ufshcd.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++ > drivers/scsi/ufs/ufshci.h | 2 + > 2 files changed, 95 insertions(+) > Reviewed-by: Hannes Reinecke <hare@xxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
