Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756152Ab1EQSYI (ORCPT ); Tue, 17 May 2011 14:24:08 -0400 Received: from out3.smtp.messagingengine.com ([66.111.4.27]:34472 "EHLO out3.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756074Ab1EQSYG (ORCPT ); Tue, 17 May 2011 14:24:06 -0400 X-Sasl-enc: a0klFYrhrCmHXXF2wnMsuCVURUmcj3aMYdTSQ4m4hw7p 1305656645 Date: Tue, 17 May 2011 11:23:56 -0700 From: Greg KH To: Shreshtha Kumar SAHU Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, rmk+kernel@arm.linux.org.uk, linus.walleij@stericsson.com, alan@linux.intel.com Subject: Re: [PATCHv2 1/2] amba pl011: workaround for uart registers lockup Message-ID: <20110517182356.GA17703@kroah.com> References: <20110516172958.GA13011@kroah.com> <1305609617-9524-1-git-send-email-shreshthakumar.sahu@stericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1305609617-9524-1-git-send-email-shreshthakumar.sahu@stericsson.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1248 Lines: 32 On Tue, May 17, 2011 at 10:50:17AM +0530, Shreshtha Kumar SAHU wrote: > From: Shreshtha Kumar Sahu > > This workaround aims to break the deadlock situation > which raises during continuous transfer of data for long > duration over uart with hardware flow control. It is > observed that CTS interrupt cannot be cleared in uart > interrupt register (ICR). Hence further transfer over > uart gets blocked. > > It is seen that during such deadlock condition ICR > don't get cleared even on multiple write. This leads > pass_counter to decrease and finally reach zero. This > can be taken as trigger point to run this UART_BT_WA. > > Workaround backups the register configuration, does soft > reset of UART using BIT-0 of PRCC_K_SOFTRST_SET/CLEAR > registers and restores the registers. > > This patch also provides support for uart init and exit > function calls if present. Why? You don't use these callbacks in this driver, so why add them? confused, greg k-h -- 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/