On Fri, Apr 9, 2010 at 9:14 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 9 Apr 2010, Sarah Sharp wrote: > >> > However there's nothing wrong with capping things at some reasonable >> > size. If someone tries to submit a request that violates the driver's >> > specified limit, it's their own fault. Was Ramya's very large transfer >> > a single bulk URB? Did it use scatter-gather? >> >> Yes, Ramya's transfer was one URB with a scatter-gather list of ~120 >> entries. He was working on a UASP driver that sets the max_sectors >> field in scsi_host_template to 960 or 1024, which makes some of the >> sglists very large. > > Then his driver is buggy. It should limit the length of scatter-gather > lists allowed by the host according to what the HCD can support, the > way usb-storage does: > > host->sg_tablesize = usb_stor_sg_tablesize(intf); Dear Alan, My device is a UASP device, however I am testing the default usb storage driver for maximum transfer buffer sizes as my device supports upto 1 MB transfer buffer sizes. There is a thread about the "Maximum data size in a single transfer for MS driver", which we have discussed in the month February, 2010. The link for the thread is as follows. http://marc.info/?t=126641036700002&r=3&w=2 NOTE: As we discussed in the above thread, the function, named store_max_sectors, has changed in 2.6.34-rc2 kernel version. I checked out the 2.6.34-rc2 kernel version from Sarah Sharp git as it supports the streams. Then, I tested my UASP device for default usb storage driver for 960 sectors. The xhci-large-tx branch, in Sarah Sharp git, has every thing set properly like max-sectors in the host template is set to 960. So, I did NOT change any thing and I am NOT using the UASP driver for testing the maximum sectors (960 or 1024 sector transfer buffer sizes) issue. I am using only default usb storage driver for testing the maximum sectors like 960 or 1024 issue. Please let me know, if you need any additional information. Thanks and Regards, Ramya. -- 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
