patch-2.4.22 linux-2.4.22/drivers/usb/storage/protocol.c

• Lines: 91
• Date: 2003-08-25 04:44:42.000000000 -0700
• Orig file: linux-2.4.21/drivers/usb/storage/protocol.c
• Orig date: 2002-08-02 17:39:45.000000000 -0700

diff -urN linux-2.4.21/drivers/usb/storage/protocol.c linux-2.4.22/drivers/usb/storage/protocol.c
@@ -53,6 +53,22 @@
 /***********************************************************************
  * Helper routines
  ***********************************************************************/
+ 
+static void * find_data_location(Scsi_Cmnd *srb)
+{
+	if (srb->use_sg) {
+		/*
+		 * This piece of code only works if the first page is
+		 * big enough to hold more than 3 bytes -- which is
+		 * _very_ likely.
+		 */
+		struct scatterlist *sg;
+
+		sg = (struct scatterlist *) srb->request_buffer;
+		return (void *) sg[0].address;
+	} else
+		return (void *) srb->request_buffer;
+}
 
 /* Fix-up the return data from an INQUIRY command to show 
  * ANSI SCSI rev 2 so we don't confuse the SCSI layers above us
@@ -65,21 +81,48 @@
 	if (srb->cmnd[0] != INQUIRY)
 		return;
 
-	US_DEBUGP("Fixing INQUIRY data to show SCSI rev 2\n");
+	/* oddly short buffer -- bail out */
+	if (srb->request_bufflen < 3)
+		return;
 
-	/* find the location of the data */
-	if (srb->use_sg) {
-		struct scatterlist *sg;
+	data_ptr = find_data_location(srb);
 
-		sg = (struct scatterlist *) srb->request_buffer;
-		data_ptr = (unsigned char *) sg[0].address;
-	} else
-		data_ptr = (unsigned char *)srb->request_buffer;
+	/* if it's already 2, bail */
+	if ((data_ptr[2] & 7) == 2)
+		return;
+
+	US_DEBUGP("Fixing INQUIRY data to show SCSI rev 2 - was %d\n",
+		data_ptr[2] & 7);
 
 	/* Change the SCSI revision number */
 	data_ptr[2] = (data_ptr[2] & ~7) | 2;
 }
 
+/*
+ * Fix-up the return data from a READ CAPACITY command. A Feiya reader
+ * returns a value that is 1 too large.
+ */
+static void fix_read_capacity(Scsi_Cmnd *srb)
+{
+	unsigned char *dp;
+	unsigned long capacity;
+
+	/* verify that it's a READ CAPACITY command */
+	if (srb->cmnd[0] != READ_CAPACITY)
+		return;
+
+	dp = find_data_location(srb);
+
+	capacity = (dp[0]<<24) + (dp[1]<<16) + (dp[2]<<8) + (dp[3]);
+	US_DEBUGP("US: Fixing capacity: from %ld to %ld\n",
+		capacity+1, capacity);
+	capacity--;
+	dp[0] = (capacity >> 24);
+	dp[1] = (capacity >> 16);
+	dp[2] = (capacity >> 8);
+	dp[3] = (capacity);
+}
+
 /***********************************************************************
  * Protocol routines
  ***********************************************************************/
@@ -345,6 +388,10 @@
 
 		/* fix the INQUIRY data if necessary */
 		fix_inquiry_data(srb);
+
+		/* Fix the READ CAPACITY result if necessary */
+		if (us->flags & US_FL_FIX_CAPACITY)
+			fix_read_capacity(srb);
 	}
 }