From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: Re: [PATCH 0/7] USB: serial: add wait_until_sent-support Date: Mon, 20 May 2013 12:07:03 +0200 Message-ID: <20130520100703.GB21474@localhost> References: <20130505182913.GE16818@localhost> <1367778753-22297-1-git-send-email-jhovold@gmail.com> <81D166EE-BB85-4A72-A6FA-A1F6B5633CB0@caylan.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <81D166EE-BB85-4A72-A6FA-A1F6B5633CB0@caylan.net> Sender: linux-kernel-owner@vger.kernel.org To: Caylan Larson Cc: Johan Hovold , Greg Kroah-Hartman , Peter Hurley , Stas Sergeev , Jarkko Huijts , Alan Cox , linux-usb@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" List-Id: linux-serial@vger.kernel.org On Fri, May 17, 2013 at 10:46:37AM -0500, Caylan Larson wrote: > Johan, > > I have tested these patches and the performance is much better. Thank you. Thanks for testing. The patches are already in the usb tree (usb-linus branch) and should show up in v3.10-rc soon. Johan > Tested-by: Caylan Larson > > Caylan > > > On May 5, 2013, at 1:32 PM, Johan Hovold wrote: > > > These patches add wait_until_sent-support to usb-serial, which removes > > the need to check hardware buffers in chars_in_buffer. > > > > This fixes a problem in ftdi_sio (since 3.7) where select or TIOCMOUTQ > > would take much longer than before due the hardware buffers being > > queried. > > > > Hardware buffers are also currently checked in chars_in_buffer in io_ti > > (since 3.8) and ti_usb_3410_5052 (in 3.10). > > > > Note that simply removing the hardware-buffer checks (e.g. for the > > stable trees) would break tty_wait_until_sent, which is used, for > > instance, by tcdrain, tcsendbreak, and close.