Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933301Ab1ESPJZ (ORCPT ); Thu, 19 May 2011 11:09:25 -0400 Received: from ch1ehsobe002.messaging.microsoft.com ([216.32.181.182]:33444 "EHLO CH1EHSOBE005.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932238Ab1ESPJW (ORCPT ); Thu, 19 May 2011 11:09:22 -0400 X-SpamScore: -3 X-BigFish: VS-3(zz98dKzz1202hzz8275dhz2dh2a8h668h839h61h) X-Spam-TCS-SCL: 0:0 X-Forefront-Antispam-Report: KIP:(null);UIP:(null);IPVD:NLI;H:mail.freescale.net;RD:none;EFVD:NLI Message-ID: <4DD5329C.2040200@freescale.com> Date: Thu, 19 May 2011 10:09:16 -0500 From: Timur Tabi Organization: Freescale User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.19) Gecko/20110429 Fedora/2.0.14-1.fc13 SeaMonkey/2.0.14 MIME-Version: 1.0 To: Arnd Bergmann CC: , , , , , , Subject: Re: [PATCH 6/7] tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver References: <1305813272-31826-1-git-send-email-timur@freescale.com> <1305813272-31826-7-git-send-email-timur@freescale.com> <201105191702.39919.arnd@arndb.de> In-Reply-To: <201105191702.39919.arnd@arndb.de> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 956 Lines: 26 Arnd Bergmann wrote: > Why is this using a full tty driver instead of the hvc framework that most > other hypervisor consoles use? Because HVC uses the same interface for consoles and tty, and that resulted in dropped characters if the client driver returns EAGAIN because it's output buffer is full. I posted a patch that "fixes" this, but it was rejected. Here's the original patch: http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-August/085136.html And here's the thread discussing our concerns: http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-September/thread.html (search for "fix dropping of characters when output byte channel is full") -- Timur Tabi Linux kernel developer at Freescale -- 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/