From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756396AbbBLQcK (ORCPT ); Thu, 12 Feb 2015 11:32:10 -0500 Received: from mail-qc0-f182.google.com ([209.85.216.182]:50409 "EHLO mail-qc0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755512AbbBLQcH (ORCPT ); Thu, 12 Feb 2015 11:32:07 -0500 Message-ID: <54DCD584.3010500@hurleysoftware.com> Date: Thu, 12 Feb 2015 11:32:04 -0500 From: Peter Hurley User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Sebastian Andrzej Siewior CC: Tony Lindgren , Nicolas Schichan , gregkh@linuxfoundation.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, balbi@ti.com, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 03/16] tty: serial: 8250_core: read only RX if there is something in the FIFO References: <1410377411-26656-1-git-send-email-bigeasy@linutronix.de> <1410377411-26656-4-git-send-email-bigeasy@linutronix.de> <54D8B772.1010405@freebox.fr> <54D9441B.7070403@hurleysoftware.com> <54D9F3C7.5000809@freebox.fr> <54DA43F8.9090904@hurleysoftware.com> <54DBB531.2030504@hurleysoftware.com> <20150211200313.GE2531@atomide.com> <54DBBE9E.90104@hurleysoftware.com> <54DC6832.3070507@linutronix.de> In-Reply-To: <54DC6832.3070507@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/12/2015 03:45 AM, Sebastian Andrzej Siewior wrote: > On 02/11/2015 09:42 PM, Peter Hurley wrote: > >>> Reverting makes sense to me if it has caused a regression. Maybe Sebastian >>> can update his patch to do this based on some quirk flag instead? >> >> That's fine with me. There's a 'bugs' field in struct 8250_uart_port and >> UART_BUG_* defines in 8250/8250.h for that purpose. > > Makes sense. Reading an empty FIFO does not look right. Maybe we should > do the bug flag the other way around? But I can do what I am told to so > if there is more fallout than just this Marvell UART I could come > around with a patch to the bug field for the older OMAP. I agree with Russell on this; better to stick with the rx read that's been running on 20 years of hardware. That said, I don't think serial8250_do_startup() is really doing that much for OMAP h/w startup; open-coding what omap_8250 really needs is probably < 10 loc. Regards, Peter Hurley