The ESP FIFO is used as a buffer for DMA requests and so isn't guaranteed to be empty in the case of SCSI errors or a mixed DMA/non-DMA request. Flush the FIFO before sending a SCSI command to guarantee that it is correctly positioned at the start of the FIFO.
Signed-off-by: Mark Cave-Ayland mark.cave-ayland@ilande.co.uk Reviewed-by: Paolo Bonzini pbonzini@redhat.com --- src/hw/esp-scsi.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/src/hw/esp-scsi.c b/src/hw/esp-scsi.c index cc25f22..e4815aa 100644 --- a/src/hw/esp-scsi.c +++ b/src/hw/esp-scsi.c @@ -46,6 +46,7 @@ #define ESP_DMA_WMAC 0x58c
#define ESP_CMD_DMA 0x80 +#define ESP_CMD_FLUSH 0x01 #define ESP_CMD_RESET 0x02 #define ESP_CMD_TI 0x10 #define ESP_CMD_ICCS 0x11 @@ -96,6 +97,9 @@ esp_scsi_process_op(struct disk_op_s *op)
outb(target, iobase + ESP_WBUSID);
+ /* Clear FIFO before sending command. */ + outb(ESP_CMD_FLUSH, iobase + ESP_CMD); + /* * We need to pass the LUN at the beginning of the command, and the FIFO * is only 16 bytes, so we cannot support 16-byte CDBs. The alternative