linux-kernel - Re: [PATCH take 2] [USB] Use normalized sense when emulating autosense

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Date:	Fri, 2 Sep 2011 14:24:36 +0800
From:	Daniel J Blueman <daniel.blueman@...il.com>
To:	Greg KH <greg@...ah.com>,
	Matthew Dharm <mdharm-usb@...-eyed-alien.net>,
	Luben Tuikov <ltuikov@...oo.com>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux USB <linux-usb-devel@...ts.sourceforge.net>,
	usb-storage@...ts.one-eyed-alien.net
Subject: Re: [PATCH take 2] [USB] Use normalized sense when emulating autosense

Hi Luben, Greg, Matthew,

Any plan for reviewing and accepting this patch [1] yet? I'm still
seeing the symptoms on USB 3 SATA bridges with linux-3.0+.

Thanks,
  Daniel

--- [1]

http://www.kerneltrap.com/mailarchive/linux-kernel/2010/11/11/4644097/thread

This patch solves two things:
1) Enables autosense emulation code to correctly
interpret descriptor format sense data, and
2) Fixes a bug whereby the autosense emulation
code would overwrite descriptor format sense data
with SENSE KEY HARDWARE ERROR in fixed format, to
incorrectly look like this:

Oct 21 14:11:07 localhost kernel: sd 7:0:0:0: [sdc]  Sense Key :
Recovered Error [current] [descriptor]
Oct 21 14:11:07 localhost kernel: Descriptor sense data with sense
descriptors (in hex):
Oct 21 14:11:07 localhost kernel:        72 01 04 1d 00 00 00 0e 09 0c
00 00 00 00 00 00
Oct 21 14:11:07 localhost kernel:        00 4f 00 c2 00 50
Oct 21 14:11:07 localhost kernel: sd 7:0:0:0: [sdc]  ASC=0x4 ASCQ=0x1d

Signed-off-by: Luben Tuikov <ltuikov@...oo.com>
---
 drivers/usb/storage/transport.c |   34 +++++++++++++++++++---------------
 1 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index 64ec073..cb04664 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -691,6 +691,9 @@ void usb_stor_invoke_transport(struct scsi_cmnd
*srb, struct us_data *us)
 		int temp_result;
 		struct scsi_eh_save ses;
 		int sense_size = US_SENSE_SIZE;
+		struct scsi_sense_hdr sshdr;
+		const u8 *scdd;
+		u8 fm_ili;

 		/* device supports and needs bigger sense buffer */
 		if (us->fflags & US_FL_SANE_SENSE)
@@ -774,32 +777,30 @@ Retry_Sense:
 			srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
 		}

+		scsi_normalize_sense(srb->sense_buffer, SCSI_SENSE_BUFFERSIZE,
+				     &sshdr);
+
 		US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
 		US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
-			  srb->sense_buffer[0],
-			  srb->sense_buffer[2] & 0xf,
-			  srb->sense_buffer[12],
-			  srb->sense_buffer[13]);
+			  sshdr.response_code, sshdr.sense_key,
+			  sshdr.asc, sshdr.ascq);
 #ifdef CONFIG_USB_STORAGE_DEBUG
-		usb_stor_show_sense(
-			  srb->sense_buffer[2] & 0xf,
-			  srb->sense_buffer[12],
-			  srb->sense_buffer[13]);
+		usb_stor_show_sense(sshdr.sense_key, sshdr.asc, sshdr.ascq);
 #endif

 		/* set the result so the higher layers expect this data */
 		srb->result = SAM_STAT_CHECK_CONDITION;

+		scdd = scsi_sense_desc_find(srb->sense_buffer,
+					    SCSI_SENSE_BUFFERSIZE, 4);
+		fm_ili = (scdd ? scdd[3] : srb->sense_buffer[2]) & 0xA0;
+
 		/* We often get empty sense data.  This could indicate that
 		 * everything worked or that there was an unspecified
 		 * problem.  We have to decide which.
 		 */
-		if (	/* Filemark 0, ignore EOM, ILI 0, no sense */
-				(srb->sense_buffer[2] & 0xaf) == 0 &&
-			/* No ASC or ASCQ */
-				srb->sense_buffer[12] == 0 &&
-				srb->sense_buffer[13] == 0) {
-
+		if (sshdr.sense_key == 0 && sshdr.asc == 0 && sshdr.ascq == 0 &&
+		    fm_ili == 0) {
 			/* If things are really okay, then let's show that.
 			 * Zero out the sense buffer so the higher layers
 			 * won't realize we did an unsolicited auto-sense.
@@ -814,7 +815,10 @@ Retry_Sense:
 			 */
 			} else {
 				srb->result = DID_ERROR << 16;
-				srb->sense_buffer[2] = HARDWARE_ERROR;
+				if ((sshdr.response_code & 0x72) == 0x72)
+					srb->sense_buffer[1] = HARDWARE_ERROR;
+				else
+					srb->sense_buffer[2] = HARDWARE_ERROR;
 			}
 		}
 	}
-- 
Daniel J Blueman
--
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