Disk enclosures with Genesys Logics chipset require additional delays, or
commands are not processed. Also, their maximum transfer size is limited.
Patch by Martin Strigl.
diff -urpN -X dontdiff linux-2.4.29/drivers/usb/storage/transport.c
linux-2.4.29-usb/drivers/usb/storage/transport.c
--- linux-2.4.29/drivers/usb/storage/transport.c 2004-11-22
23:04:19.000000000 -0800
+++ linux-2.4.29-usb/drivers/usb/storage/transport.c 2005-01-26
12:45:30.000000000 -0800
@@ -1181,6 +1181,13 @@ int usb_stor_Bulk_transport(Scsi_Cmnd *s
/* if the command transfered well, then we go to the data stage */
if (result == 0) {
+
+ /* Genesys Logic interface chips need a 100us delay between
+ * the command phase and the data phase. Some systems need
+ * even more, probably because of clock rate inaccuracies. */
+ if (us->pusb_dev->descriptor.idVendor == USB_VENDOR_ID_GENESYS)
+ udelay(110);
+
/* send/receive data payload, if there is any */
if (bcb->DataTransferLength) {
usb_stor_transfer(srb, us);
diff -urpN -X dontdiff linux-2.4.29/drivers/usb/storage/usb.c
linux-2.4.29-usb/drivers/usb/storage/usb.c
--- linux-2.4.29/drivers/usb/storage/usb.c 2004-11-22 23:04:19.000000000
-0800
+++ linux-2.4.29-usb/drivers/usb/storage/usb.c 2005-01-26 12:45:30.000000000
-0800
@@ -996,6 +996,15 @@ static void * storage_probe(struct usb_d
*/
ss->htmplt.proc_dir = (void *)ss;
+ /* According to the technical support people at Genesys Logic,
+ * devices using their chips have problems transferring more
+ * than 32 KB at a time. In practice people have found that
+ * 64 KB works okay and that's what Windows does. But we'll
+ * be conservative.
+ */
+ if (ss->pusb_dev->descriptor.idVendor == USB_VENDOR_ID_GENESYS)
+ ss->htmplt.max_sectors = 64;
+
/* Just before we start our control thread, initialize
* the device if it needs initialization */
if (unusual_dev && unusual_dev->initFunction)
diff -urpN -X dontdiff linux-2.4.29/drivers/usb/storage/usb.h
linux-2.4.29-usb/drivers/usb/storage/usb.h
--- linux-2.4.29/drivers/usb/storage/usb.h 2005-01-05 00:59:27.000000000
-0800
+++ linux-2.4.29-usb/drivers/usb/storage/usb.h 2005-01-26 13:04:40.000000000
-0800
@@ -193,4 +193,7 @@ extern struct usb_driver usb_storage_dri
/* Function to fill an inquiry response. See usb.c for details */
extern void fill_inquiry_response(struct us_data *us,
unsigned char *data, unsigned int data_len);
+
+/* Vendor ID list for devices that require special handling */
+#define USB_VENDOR_ID_GENESYS 0x05e3 /* Genesys Logic */
#endif
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