* Alternate ways to do Scatter-Gather from BOT Class driver @ 2010-06-28 16:29 Subs 2010-06-28 18:55 ` Alan Stern 0 siblings, 1 reply; 4+ messages in thread From: Subs @ 2010-06-28 16:29 UTC (permalink / raw) To: linux-usb, linux-scsi Hi All, In my class driver I am receiving data transfer buffer as number of Scatter-Gather lists from SCSI layer to perform data transfers. Is there any alternate way to get the transfer buffer from SCSI other than SG. I wanted to receive the complete data transfer buffer as a single pointer. -Subs ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Alternate ways to do Scatter-Gather from BOT Class driver 2010-06-28 16:29 Alternate ways to do Scatter-Gather from BOT Class driver Subs @ 2010-06-28 18:55 ` Alan Stern 2010-06-29 15:00 ` Subs 0 siblings, 1 reply; 4+ messages in thread From: Alan Stern @ 2010-06-28 18:55 UTC (permalink / raw) To: Subs; +Cc: linux-usb, linux-scsi On Mon, 28 Jun 2010, Subs wrote: > Hi All, > > In my class driver I am receiving data transfer buffer as number of > Scatter-Gather lists from SCSI layer to perform data transfers. > > Is there any alternate way to get the transfer buffer from SCSI other > than SG. I wanted to receive the complete data transfer buffer as a > single pointer. As far as I know, there is no alternate way to get the transfer buffer from the SCSI layer. However you can get the effect you want by setting the sg_tablesize field in your scsi_host_template to 1. Just out of curiosity, why are you writing a class driver for the BOT class? Aren't the two existing drivers in the kernel good enough? Alan Stern ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Alternate ways to do Scatter-Gather from BOT Class driver 2010-06-28 18:55 ` Alan Stern @ 2010-06-29 15:00 ` Subs [not found] ` <AANLkTilIM-9svLKrqaPfsjESn_9VnqsffBDwtiau8B_3-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 0 siblings, 1 reply; 4+ messages in thread From: Subs @ 2010-06-29 15:00 UTC (permalink / raw) To: Alan Stern; +Cc: linux-usb, linux-scsi On Tue, Jun 29, 2010 at 12:25 AM, Alan Stern <stern@rowland.harvard.edu> wrote: > On Mon, 28 Jun 2010, Subs wrote: > >> Hi All, >> >> In my class driver I am receiving data transfer buffer as number of >> Scatter-Gather lists from SCSI layer to perform data transfers. >> >> Is there any alternate way to get the transfer buffer from SCSI other >> than SG. I wanted to receive the complete data transfer buffer as a >> single pointer. > > As far as I know, there is no alternate way to get the transfer buffer > from the SCSI layer. > > However you can get the effect you want by setting the sg_tablesize > field in your scsi_host_template to 1. > > Just out of curiosity, why are you writing a class driver for the BOT > class? Aren't the two existing drivers in the kernel good enough? > > Alan Stern > > By changing sg_tablesize to 1, there is no change in number of buffers that I am receiving in SG list. > Just out of curiosity, why are you writing a class driver for the BOT > class? Aren't the two existing drivers in the kernel good enough? I am writing my custom class driver, which can do Control and Bulk transfers only. This is nowhere related to Mass Storage BOT transfers. Regards, Subs -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <AANLkTilIM-9svLKrqaPfsjESn_9VnqsffBDwtiau8B_3-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>]
* Re: Alternate ways to do Scatter-Gather from BOT Class driver [not found] ` <AANLkTilIM-9svLKrqaPfsjESn_9VnqsffBDwtiau8B_3-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> @ 2010-06-29 18:06 ` Alan Stern 0 siblings, 0 replies; 4+ messages in thread From: Alan Stern @ 2010-06-29 18:06 UTC (permalink / raw) To: Subs; +Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA, linux-scsi-u79uwXL29TY76Z2rM5mHXA On Tue, 29 Jun 2010, Subs wrote: > On Tue, Jun 29, 2010 at 12:25 AM, Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLrNAH6kLmebB@public.gmane.orgdu> wrote: > > On Mon, 28 Jun 2010, Subs wrote: > > > >> Hi All, > >> > >> In my class driver I am receiving data transfer buffer as number of > >> Scatter-Gather lists from SCSI layer to perform data transfers. > >> > >> Is there any alternate way to get the transfer buffer from SCSI other > >> than SG. I wanted to receive the complete data transfer buffer as a > >> single pointer. > > > > As far as I know, there is no alternate way to get the transfer buffer > > from the SCSI layer. > > > > However you can get the effect you want by setting the sg_tablesize > > field in your scsi_host_template to 1. > > > > Just out of curiosity, why are you writing a class driver for the BOT > > class? Aren't the two existing drivers in the kernel good enough? > > > > Alan Stern > > > > > > By changing sg_tablesize to 1, there is no change in number of buffers > that I am receiving in SG list. Then you must be doing something wrong. I just tried changing sg_tablesize in the usb-storage driver, and as a result the scatterlists it received contained only one element. (Of course, in usb-storage what matters is not the value in the scsi_host_template but rather the value returned by usb_stor_sg_tablesize.) > > Just out of curiosity, why are you writing a class driver for the BOT > > class? Aren't the two existing drivers in the kernel good enough? > > I am writing my custom class driver, which can do Control and Bulk > transfers only. This is nowhere related to Mass Storage BOT transfers. Then why did you mention BOT in the email Subject: line? Does it refer to something other than Bulk-Only-Transport? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-06-29 18:06 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2010-06-28 16:29 Alternate ways to do Scatter-Gather from BOT Class driver Subs 2010-06-28 18:55 ` Alan Stern 2010-06-29 15:00 ` Subs [not found] ` <AANLkTilIM-9svLKrqaPfsjESn_9VnqsffBDwtiau8B_3-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2010-06-29 18:06 ` Alan Stern
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