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From: Alan Stern <stern@rowland.harvard.edu>
To: Suwan Kim <suwan.kim027@gmail.com>
Cc: mathias.nyman@linux.intel.com, <linux-usb@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2] usb: host: xhci: Support running urb giveback in tasklet context
Date: Mon, 1 Apr 2019 10:43:24 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1904011040570.1506-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20190401141611.10087-1-suwan.kim027@gmail.com>

On Mon, 1 Apr 2019, Suwan Kim wrote:

> Patch "USB: HCD: support giveback of URB in tasklet context"[1]
> introduced giveback of urb in tasklet context. [1] This patch was
> applied to ehci but not xhci. [2] This patch significantly reduces
> the hard irq time of xhci. Especially for uvc driver, the hard irq
> including the uvc completion function runs quite long but applying
> this patch reduces the hard irq time of xhci.

Please read the kerneldoc for usb_submit_urb() and usb_kill_urb(), in 
particular, the parts that describe how isochronous URBs are treated.  
Can you guarantee that with this patch applied, xhci-hcd will continue 
to work as the kerneldoc describes?

Alan Stern


  reply	other threads:[~2019-04-01 14:43 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-01 14:16 Suwan Kim
2019-04-01 14:43 ` Alan Stern [this message]
2019-04-04 12:18   ` Suwan Kim
2019-04-04 20:54     ` Alan Stern
2019-04-08 14:26       ` Suwan Kim
2019-05-07 16:02 ` Suwan Kim
2019-05-08 12:04   ` Mathias Nyman
2019-05-08 14:40     ` Suwan Kim

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