diff options
Diffstat (limited to 'drivers/usb/storage/transport.c')
| -rw-r--r-- | drivers/usb/storage/transport.c | 43 |
1 files changed, 40 insertions, 3 deletions
diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c index 22c7d4360fa2..540add24a12f 100644 --- a/drivers/usb/storage/transport.c +++ b/drivers/usb/storage/transport.c @@ -1035,9 +1035,20 @@ int usb_stor_Bulk_max_lun(struct us_data *us) usb_stor_dbg(us, "GetMaxLUN command result is %d, data is %d\n", result, us->iobuf[0]); - /* if we have a successful request, return the result */ - if (result > 0) - return us->iobuf[0]; + /* + * If we have a successful request, return the result if valid. The + * CBW LUN field is 4 bits wide, so the value reported by the device + * should fit into that. + */ + if (result > 0) { + if (us->iobuf[0] < 16) { + return us->iobuf[0]; + } else { + dev_info(&us->pusb_intf->dev, + "Max LUN %d is not valid, using 0 instead", + us->iobuf[0]); + } + } /* * Some devices don't like GetMaxLUN. They may STALL the control @@ -1118,6 +1129,31 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us) */ if (result == USB_STOR_XFER_LONG) fake_sense = 1; + + /* + * Sometimes a device will mistakenly skip the data phase + * and go directly to the status phase without sending a + * zero-length packet. If we get a 13-byte response here, + * check whether it really is a CSW. + */ + if (result == USB_STOR_XFER_SHORT && + srb->sc_data_direction == DMA_FROM_DEVICE && + transfer_length - scsi_get_resid(srb) == + US_BULK_CS_WRAP_LEN) { + struct scatterlist *sg = NULL; + unsigned int offset = 0; + + if (usb_stor_access_xfer_buf((unsigned char *) bcs, + US_BULK_CS_WRAP_LEN, srb, &sg, + &offset, FROM_XFER_BUF) == + US_BULK_CS_WRAP_LEN && + bcs->Signature == + cpu_to_le32(US_BULK_CS_SIGN)) { + usb_stor_dbg(us, "Device skipped data phase\n"); + scsi_set_resid(srb, transfer_length); + goto skipped_data_phase; + } + } } /* See flow chart on pg 15 of the Bulk Only Transport spec for @@ -1153,6 +1189,7 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us) if (result != USB_STOR_XFER_GOOD) return USB_STOR_TRANSPORT_ERROR; + skipped_data_phase: /* check bulk status */ residue = le32_to_cpu(bcs->Residue); usb_stor_dbg(us, "Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n", |