From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <8ccc8ba40907190207n2bd97032ra267bff7e45f7813@mail.gmail.com> Date: Sun, 19 Jul 2009 13:30:25 +0200 Message-ID: <8ccc8ba40907190430x4254dc49l5c41c0e47b4587c@mail.gmail.com> From: Francisco J Ballesteros To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] new usb stack and implicit timeouts Topicbox-Message-UUID: 2713b3fc-ead5-11e9-9d60-3106f5b1d025 > other end has something to send. =C2=A0Have you seen anything in the USB > spec which indicates a timeout for reading from a bulk pipe is > appropriate? > No. All devices I had tested at that time required a time out. Ethernet came later. I think it's better to remove the timeout from bulk endpoints (perhaps by making it optional) and leave it there in the case of control requests. I was just waiting to september, to give it time to the current code to show wichever bugs it may have. Perhaps is better not to wait. I strongly argue in favor of in-kernel ctl timeouts. Otherwise programs lik= e usbd (and all drivers) will have a bad time. Moreover, I've seen devices that block on particular requests but crash if you interrupt them at bad times. The kernel is careful to interrupt the control transfers without bothering the device much.