From: Greg KH <greg@kroah.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Jason Wessel <jason.wessel@windriver.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] usb_debug: EXPERIMENTAL - poll hcd device to force writes
Date: Wed, 6 May 2009 08:45:06 -0700 [thread overview]
Message-ID: <20090506154506.GB4941@kroah.com> (raw)
In-Reply-To: <20090506164141.55c8978c@lxorguk.ukuu.org.uk>
On Wed, May 06, 2009 at 04:41:41PM +0100, Alan Cox wrote:
> In other words never lie in the write_room method. Try to send data as
> early as possible, but don't queue data inefficiently when the port has
> plenty left to send.
>
> The rules for write_room are simple
>
> If you say you have space for X bytes you can't say you have room
> for less bytes unless those bytes have actually been written - no
> window shrinking so to speak.
>
> If your write_room method works properly, and you fix the buffering logic
> then the rest will work. Probably we need usb/serial/buffer.c which has a
> generic implementation in then that can be used to replace the completely
> bogus hacks in most of the drivers.
I agree, this is the correct solution.
thanks,
greg k-h
next prev parent reply other threads:[~2009-05-06 15:48 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-06 2:00 [PATCH 0/5] usb_debug driver improvements Jason Wessel
2009-05-06 2:00 ` [PATCH 1/5] usb_debug: implement multi urb write Jason Wessel
2009-05-06 2:00 ` [PATCH 2/5] usb_debug,usb_generic_serial: implement sysrq and serial break Jason Wessel
2009-05-06 2:00 ` [PATCH 3/5] usb,early_printk: insert cr prior to nl as needed Jason Wessel
2009-05-06 2:00 ` [PATCH 4/5] usb,early_printk: unregister early usb before rest_init() Jason Wessel
2009-05-06 2:00 ` [PATCH 5/5] usb_debug: EXPERIMENTAL - poll hcd device to force writes Jason Wessel
2009-05-06 15:18 ` Alan Stern
2009-05-06 15:25 ` Greg KH
2009-05-06 15:42 ` Alan Cox
2009-05-06 15:59 ` Jason Wessel
2009-05-06 15:41 ` Alan Cox
2009-05-06 15:45 ` Greg KH [this message]
2009-05-06 17:17 ` Oliver Neukum
2009-05-06 19:24 ` Alan Stern
2009-05-06 20:01 ` Oliver Neukum
2009-05-06 20:24 ` Alan Stern
2009-05-06 22:24 ` Oliver Neukum
2009-05-07 14:35 ` Alan Stern
2009-05-07 15:01 ` Oliver Neukum
2009-05-07 16:32 ` Alan Stern
2009-05-06 20:24 ` Jason Wessel
2009-05-06 20:28 ` Greg KH
2009-05-06 20:51 ` [PATCH 5/5] usb_debug: EXPERIMENTAL - poll hcd device to forcewrites Jason Wessel
2009-05-06 21:32 ` Greg KH
2009-05-07 14:00 ` Alan Stern
2009-05-07 0:06 ` [PATCH 5/5] usb_debug: EXPERIMENTAL - poll hcd device to force writes Alan Cox
2009-05-07 14:27 ` Alan Stern
2009-05-07 14:49 ` Oliver Neukum
2009-05-06 7:34 ` [PATCH 4/5] usb,early_printk: unregister early usb before rest_init() Ingo Molnar
2009-05-06 13:02 ` Jason Wessel
2009-05-07 15:09 ` Ingo Molnar
2009-05-06 7:30 ` [PATCH 3/5] usb,early_printk: insert cr prior to nl as needed Ingo Molnar
2009-05-06 15:25 ` Greg KH
2009-05-07 15:04 ` Ingo Molnar
2009-05-06 7:16 ` [PATCH 1/5] usb_debug: implement multi urb write Oliver Neukum
2009-05-06 11:57 ` Jason Wessel
2009-05-06 12:31 ` Oliver Neukum
2009-05-06 15:26 ` Greg KH
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