On Wed, Feb 17, 2010 at 8:32 PM, James Bottomley <James.Bottomley@xxxxxxx> wrote: > I have no idea what the MS driver is, so it's impossible to answer > specifically. MS means mass storage driver only. > As long as the driver supports chaining, you increase it > in /sys/block/dev>/queue/max_sectors_kb. For compatibility reasons this > stays clamped at 512 unless a user specifically raises it. The max_sectors value is defined in struct scsi_host_template usb_stor_host_template structure in scsiglue.c file (drivers/usb/storage). If I change the max_sectors value in this scsiglue.c file it reflects in the /sys/block/<dev>/queue/max_sectors_kb and /sys/block/<dev>/queue/max_hw_sectors_kb. However, when I set the max_sectors to 1024 it reflected as 512 in /sys/block/<dev>/queue/max_sectors_kb and /sys/block/<dev>/queue/max_hw_sectors_kb. If I change the max_sectors to 1536 or 2048 in scsiglue.c file, still it reflected as 512 in /sys/block/<dev>/queue/max_sectors_kb and 768 or 1024 in /sys/block/<dev>/queue/max_hw_sectors_kb. I have changed the value in /sys/block/<dev>/queue/max_sectors_kb to 1024 with the following command. echo 1024 > /sys/block/<dev>/queue/max_sectors_kb. The file shows 1024, but still, I received only 512 KB data transfer buffers (transfer length in srb) from SCSI layer in my mass storage driver. Here, my question is, how can my mass storage driver receives the 1024 KB data transfer buffers (transfer length in srb) from SCSI layer. Please let me know. Thanks in advance. Thanks and Regards, RD -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
