On 06/15/2009 05:01 PM, Alan Stern wrote: > On Mon, 15 Jun 2009, Boaz Harrosh wrote: > >>>> If you are using the existing USB mass storage infrastructure then >>>> it will not work. This is because all commands are issued from a >>>> thread per host, which does a synchronous execution of one command >>>> at a time. In fact it does not even have a Q, but a global one cmnd >>>> pointer per host. And therefor sets can_queue to 1. >>>> >>>> Are you using the existing USB infrastructure? >>>> >>>> >>>> Boaz >>>> >>> I am replacing the default USB mass storage driver with the one I am >>> developing. But I am using the default SCSI and USB stack provided by >>> Linux. >>> >>> So is there any another way to make my driver asynchronous? >>> >>> -RD >> I was afraid so. >> >> There is a lot of code you will need to change in current USB storage stack >> SCSI is built with native support for queuing, but not so USB-storage-stack. > > Boaz: > > It looks like you didn't read Ramya's reply to your last message. > Ramya isn't keeping the USB storage "stack" -- it is being replaced by > a new driver -- so there's no point talking about making changes to it. > You are right, this is not what I understood. I understood that he is hacking on current USB driver to try and enhance it in such a way that it will support command queuing at the target. He is not currently concerned about any devices but his own HW. But he is certainly not writing a driver from scratch. He is basing on the current code base. Did I understand right? > Alan Stern > Do you think you have any tips for him. For example at the USB transport side, what is needed for asynchronous command execution as opposed to what is done now? Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
