From benh@kernel.crashing.org Wed Oct 14 10:17:59 2009 From: Benjamin Herrenschmidt Date: Tue, 13 Oct 2009 15:53:47 +1100 Subject: usb-storage: Workaround devices with bogus sense size To: Alan Stern Cc: Ben Efros , Josua Dietze , fangxiaozhi , Greg KH , Hugh Blemings Message-ID: <1255409627.2192.172.camel@pasglop> 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 Signed-off-by: Benjamin Herrenschmidt Acked-by: Alan Stern Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/storage/transport.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) --- a/drivers/usb/storage/transport.c +++ b/drivers/usb/storage/transport.c @@ -696,7 +696,7 @@ void usb_stor_invoke_transport(struct sc /* 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 sc 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");