The following commit has been merged in the linux branch: commit b8430e1b82b7e514d76a88eb70a7d8831d50df1e Author: Benjamin Herrenschmidt benh@kernel.crashing.org Date: Tue Oct 13 15:53:47 2009 +1100

usb-storage: Workaround devices with bogus sense size

usb-storage: Workaround devices with bogus sense size

Some devices, such as Huawei E169, advertise more than the standard amount of sense data, causing us to set US_FL_SANE_SENSE, assuming they support it. However, they subsequently fail the request sense with that size.

This works around it generically. When a sense request fails due to a device returning an error, US_FL_SANE_SENSE was set, and that sense request used a larger sense size, we retry with a smaller size before giving up.

Based on an original patch by Ben Efros ben@pc-doctor.com

Signed-off-by: Benjamin Herrenschmidt benh@kernel.crashing.org Acked-by: Alan Stern stern@rowland.harvard.edu Cc: stable stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@suse.de

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c index 3a4fb02..589f6b4 100644 --- a/drivers/usb/storage/transport.c +++ b/drivers/usb/storage/transport.c @@ -696,7 +696,7 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us) /* device supports and needs bigger sense buffer */ if (us->fflags & US_FL_SANE_SENSE) sense_size = ~0; - +Retry_Sense: US_DEBUGP("Issuing auto-REQUEST_SENSE\n");

scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size); @@ -720,6 +720,21 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us) srb->result = DID_ABORT << 16; goto Handle_Errors; } + + /* Some devices claim to support larger sense but fail when + * trying to request it. When a transport failure happens + * using US_FS_SANE_SENSE, we always retry with a standard + * (small) sense request. This fixes some USB GSM modems + */ + if (temp_result == USB_STOR_TRANSPORT_FAILED && + (us->fflags & US_FL_SANE_SENSE) && + sense_size != US_SENSE_SIZE) { + US_DEBUGP("-- auto-sense failure, retry small sense\n"); + sense_size = US_SENSE_SIZE; + goto Retry_Sense; + } + + /* Other failures */ if (temp_result != USB_STOR_TRANSPORT_GOOD) { US_DEBUGP("-- auto-sense failure\n");