Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751769AbaLOJwq (ORCPT ); Mon, 15 Dec 2014 04:52:46 -0500 Received: from mail-la0-f44.google.com ([209.85.215.44]:56445 "EHLO mail-la0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750865AbaLOJwm (ORCPT ); Mon, 15 Dec 2014 04:52:42 -0500 Date: Mon, 15 Dec 2014 10:52:38 +0100 From: Johan Hovold To: George McCollister Cc: Johan Hovold , linux-usb@vger.kernel.org, open list , Greg Kroah-Hartman Subject: Re: [PATCH] USB: serial: add nt124 usb to serial driver Message-ID: <20141215095238.GB6778@localhost> References: <1418081057-25283-1-git-send-email-george.mccollister@gmail.com> <20141210130412.GJ14346@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 14, 2014 at 11:51:11AM -0600, George McCollister wrote: > Johan, > > While working on the tx_empty changes you suggested it occurred to me > that it might not be obvious to others that the firmware doesn't send > a packet with the NT124_CTRL_TXEMPTY flag cleared when it begins > transmitting. The practical implication is that if the driver sets > tx_empty = true when it sees NT124_CTRL_TXEMPTY, tx_empty must be > reset to false somewhere when more data is transmitted. Perhaps I > could add prepare_write_buffer and do it in there before calling > usb_serial_generic_prepare_write_buffer(). Does that sound acceptable? Hmm. There's no way to query that flag? And the status is sent (as bulk in data) periodically or only when data has been received? And not when the actual status changes? A potential problem with using prepare_write_buffer would be on failures to submit the write urb, in which case this flag might never be cleared. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/