From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752020AbcF1Dyz (ORCPT ); Mon, 27 Jun 2016 23:54:55 -0400 Received: from mail-am1on0138.outbound.protection.outlook.com ([157.56.112.138]:9032 "EHLO emea01-am1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751673AbcF1Dyw (ORCPT ); Mon, 27 Jun 2016 23:54:52 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=bhuvanchandra.dv@toradex.com; Subject: Re: [PATCH 1/8] tty: serial: fsl_lpuart: consider TX FIFO too in tx_empty To: Greg KH References: <20160609151039.20817-1-bhuvanchandra.dv@toradex.com> <20160609151039.20817-2-bhuvanchandra.dv@toradex.com> <20160625212600.GA28726@kroah.com> CC: , , , , , , , , , From: Bhuvanchandra DV Message-ID: Date: Tue, 28 Jun 2016 09:24:00 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <20160625212600.GA28726@kroah.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [115.115.243.34] X-ClientProxiedBy: HK2PR01CA0116.apcprd01.prod.exchangelabs.com (10.167.63.170) To HE1PR0501MB2089.eurprd05.prod.outlook.com (10.167.246.9) X-MS-Office365-Filtering-Correlation-Id: 50f200ce-0373-4d20-31f2-08d39f07f2c6 X-Microsoft-Exchange-Diagnostics: 1;HE1PR0501MB2089;2:yGjt9gQ85iCrUaxlYnnQOV//ImNj8svpsgfAzaZPKt3GsltNsKCGeFRlGqBe4L6LkKU7aCCvfeHTXN54TgQDCptgXlqyMgLShe8OQMrQrBnzucWAyg0kcf1OTkNImjuxDtzwtEqYHaxM+4Tumec9HqQtACGbooMR1ucXVBiZ7jlwD1kKAURhddNvrkewK4hA;3:Hct9yVQTB1ArADk//GpSbC70IVNpfSsq1tba0aDW8080nYvyYqFVJI5vut+mgUD7OYB+JsqgoY7TIY01P9YWCIDDvqKGbg0SbIDiQ5wbYQAXBRJu0fg5QxTymqETwHNW X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:HE1PR0501MB2089; X-Microsoft-Exchange-Diagnostics: 1;HE1PR0501MB2089;25:Bwyoe1WVvHuH6mP6BRucxgb4l3JCWJ+LJbl4umOpXav0CX3CS8ddoQd+fqFhTuhXAWpTVzlpikzrzcUecVN24VEGA++xN6pn/Vr995uY/uaasPQfLukBMks+5r9u3+0aCHY6Equ8mtpMyvTXdosAaDY4iXYOCebWV5sY3m6Ys7ns6Efu2nKh+7mUhfTJ+xbtYm1LzsKsKREkmFjNQ3tmuyRux3mlRWajnFdpO6MIJUt2kiHL9KQkMBGHdRO/TdC/h4R8S+t52SGb5ocrsx7GxCGm9nQL9oSljBu+Sg5zQ8DcWHF3dB2rB6+W/fJkV3/P91c76FZiTDk886R1GFIgh//48FEUr3uWJAwBPf530yhW1lq/cFPFSeZf1TnbpexNWJE85jn0GkY9WxK63aqqi/W1i7IhdZw7+lkfJzV6SLhX1pWeD80OiKRXXatkre9JeWRbkMzFsNvrGSg2/bEeMCu3384mOE8N2y3Y2D/j2qfWynEUk/X/7EeQznfLiyM2aIPmeQ6wfY4V4vca3aOvYZcffEuYGbHVrwB03xe2Itz+iXAQrOW6AD8Ao1+O7Qp47VeURCAT8OdgaX8ZnnlMC5dYkQ9MJ66sXizGSH9HqbMaV5hyXrHt7pUdtaMrrxX6jZFGvI+w5YBMBvVgV2PxN/urgvee4L+sUr1jQQ4kNYM1MPIVAPzHzMPAnqeDK4aFQKi/Or5Wb0zjzS9dZ+laZap9C0o2+I5T7GylzV3hnXM= X-Microsoft-Exchange-Diagnostics: 1;HE1PR0501MB2089;20:A+xfb7Rcg1g3Ki/b0+SQrdXQ3+0QbSnW2xAJHkUBuqk5/w6DxQ2RJVP3XrSb0q0jtsLqUHZ7PFbLdSU+B2PCK95kBGAR+E7j7Lr+vBcbXwXi5hEFjVVKSULUcSNPZcNrFQ2wzl1nxL/SCG9dBUezFHgrXxxTF7FacZwplYqlMoh3RSxZRsoEKZlRiAeLfh+kZDRfyigzB3Vl3uJyKwzsvEzArMQen5gnjQdBOhk1jOwnEOlix6GF/RS2fzKwG7jTcM52UXAOQwWBxVwgCO6iiXRhWFobYjJk77j7sLRkVFiGdXwIjvKB5fU3SpYNR16eZniXSqjBzthXGRJeJb94uA==;4:ECAyKneYi3pB30wIDCfNJsnPSLHNxe+734k3Mn4o64yinOMz/YB08A7gOnYZ8Mu1+ZvERAyi9xCKCbh1oqTIr5qEjcv1iDB9SaEI2VzPcBxNA5S+sog3RoBVBq0pV7N0NM5upSBplSLq03yhVSuQxRXJwN4Z2MozpPL8vRQ0cckFKui22Z3Ie/Xg9qzijnJkX030KxbewHKJya2E3VKDBthexmSl51tSVMq1o/7o4PB185PVzfJkccK6TrjJDWHWD+T4wX8XtmsAIqi2Jf6r+ITdYHrx6zEIuox6uEQ5VHL43POb2z9gy7igZ7yd7dU+HbeWlBFhBDc62NvB5qJaKONHV0xnkwyl1vt6PCjTa77cWVzMMYxN+hFhRMh5muVA X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(5005006)(8121501046)(10201501046)(3002001);SRVR:HE1PR0501MB2089;BCL:0;PCL:0;RULEID:;SRVR:HE1PR0501MB2089; X-Forefront-PRVS: 0987ACA2E2 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(4630300001)(6049001)(6009001)(7916002)(199003)(24454002)(189002)(4326007)(7736002)(230700001)(83506001)(23746002)(68736007)(31686004)(31696002)(305945005)(106356001)(2906002)(4001350100001)(19580395003)(19580405001)(42186005)(97736004)(8676002)(65806001)(36756003)(33646002)(65956001)(101416001)(47776003)(110136002)(189998001)(66066001)(7846002)(105586002)(2950100001)(77096005)(64126003)(86362001)(81166006)(54356999)(3846002)(6116002)(92566002)(76176999)(81156014)(50466002)(586003)(50986999)(65826006);DIR:OUT;SFP:1102;SCL:1;SRVR:HE1PR0501MB2089;H:[10.18.0.138];FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en; X-Microsoft-Exchange-Diagnostics: =?Windows-1252?Q?1;HE1PR0501MB2089;23:RPJK3Cr2sVkczk3iVFt76a7zb2K+ZmuMasF?= =?Windows-1252?Q?X2kUYjmZFTyn/0myAim8nto4nDnqHv/sBnBOum4lTX3JebYi//GISx4V?= =?Windows-1252?Q?RsD932hui5rD/06JqiLTE/zlnI3arfE/hfwuyRaTAoiJ/NdCTcF+gFGP?= =?Windows-1252?Q?OqeXCZCmF4C2mHfDT/NbYnTrhvJlyki9/SDnyMPLPCt2+Xg56aq4CfSZ?= =?Windows-1252?Q?QQgMsWQQ3rFrRYxK7GwD/SpGlZY5O/NDQ8FKtQpnHNy1AXq+P7kNXwQe?= =?Windows-1252?Q?MdJLbTCi+MOt85KMM5ngZj9TV9BXrTey2FPqetDxwHAJjrLgMMlUiG1P?= =?Windows-1252?Q?ePPFxYofssF0ORSbmgO3d2Xmi0hD63Tlr/g3ITEzG5gZ//aJgVhS+RMO?= =?Windows-1252?Q?DtQHCkBvWiiy0f6IBbTK6TEs/2HihIrsJ9Elc+fIz2JsonfASsI3f8ex?= =?Windows-1252?Q?5DIFEGi1aoHwrW409MssKhLtAy3IpqfuQ0FG6S0VxM2PTssbAf47h253?= =?Windows-1252?Q?cq2TU1SpwMQsCjM4g/aQo3uS6FAXVXgUobmtx3np5oLkcNGM8ILXIw7y?= =?Windows-1252?Q?sBBT/h4kmXHPPMmDLgZb+cSaEmtmGKv/vuQhn4kpkwlA7Vo1r6yMqE3B?= =?Windows-1252?Q?5ZUmcr4LldVu/GSGTOKPzqb0tu9t9B74T3JhktQjds5l7Vnu826CXazb?= =?Windows-1252?Q?7hPOEPBIoIg+HGGM6oU6gsEA/mQmpBcKTJ+o2q1Ur31JojMdjt29t2IS?= =?Windows-1252?Q?wCd+j5m3rmcpGjDctJl9U/F3K2gZI7Pl+0tjyibB7mkqtFMp5sRu16gR?= =?Windows-1252?Q?fsnk1C3tAW4ky04CSYblQp+jTLF4IoQFHP83SyXW8KP3BINiBx2RMWBw?= =?Windows-1252?Q?XS1z6DYxzEdadRgd6p88Fb2A1FAGbgluAeRSZKZS/Rdf3wp012CLGxey?= =?Windows-1252?Q?kf9eytioGQkoi6BWXwmHi60gXoRQeeMHoiTfubE1Z7odfqs/HfOwufLM?= =?Windows-1252?Q?JkfxqyEcukGk2VXgas7S9gBWFoqPK6wlmHbfG5ABy1WagDufYUj6Im89?= =?Windows-1252?Q?9MWn7WRMVhLeiUPpBhIRA/cvZkwEFMxLUaEnd58ka6jnKEPCIoQNDeps?= =?Windows-1252?Q?orkVuz3emA9Fx2cB4ALhe6Yy/SfO8l7Bqc0IGymEtuy/Xr7DDDgw89jH?= =?Windows-1252?Q?BbX83Yk1zg7DbNR3G7ANUK8MseTsUjIX2oEGWfV//Dax5eu95JGHnJYD?= =?Windows-1252?Q?ciir7uKiiMpuF8KiL5bbZLEPW2MloKDCjjSNEHPNrKzMdTArvWDRellI?= =?Windows-1252?Q?uitX0ZuukMP8URhoBajpZd56Sf80yilk/R37t4FBjema4jG4=3D?= X-Microsoft-Exchange-Diagnostics: 1;HE1PR0501MB2089;6:lMmZcOZgbd77HtmcLdEl+qNv6bh5wuPRnZmEmZzyUHLIuxoCD042iKYzKFLy4oQ2p0wudhrQLDTjH2Ue0NM/gnE9/DF1OnFW4t5j5fTtPXIb7hSIaaQ8x+OW6xkTxnbDS6BmtzE9aNeZpYlSdB4DiyEVBr7HiwT/Lph1G4FpTR18Zl6RFbISGp52UtxXhMUoHaRfQjpYaFQVSQBEStK49HSmWQbGNbYTLm1vyo9FDvR+LzMeDUwGWd92HH2MT5kKsIaeELUhmwiU8zLG96nCimNbUK51r17Xj26dNbYNuODjVo+vPH5uqY7rDz3jYrxD;5:KsNvZVwGV0AikOHjsWHZqCUbfvIwC8pHTCwBJ73WnJ16XnAIARU3v8oewCg7h/KykEj/2RwUKbOKw+AvLvzdjqMNlwcNZ1JTnxd8GcrYVCUMFQGXgZ26bFPstHTdg1O7l9h53lot81PnwCHDFBLVGA==;24:rhx1qHle03J48PJnDw7cLA7zeUd1jFzoJ9a0J0ZpzR3uo69Mv7iqvrG8gOdDr6wZM4APpmKcfuQSRd+U5NukgU9fvKn8x3329yH1AfRIQjE=;7:cyznZk3mq1f/H8ZDxVNzgaDy3xrM/FkCj0hsGNlb8axWP9PzSeCgocUuDQFaQ0LyEM1InjvSNQfICReHtZtcH8nyiChA/TuJ2oTpzYO02xIOu2d83viHGkmBJ2kPpasgCgh9+osRgbXRcU+Z/Uwr6OpZKRFRz0ldhO6Pi8rL0JlDWTxzNjplAcogyjKSwGHjiPhGDGXj9jV+Wz/4CcYSbI4fZr3+roGN/1pBWP771kBf4NY2o3tvA/siVeRhBgkir9CT7THGaRLKQG5KFPdy3A== SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: toradex.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Jun 2016 03:54:42.2366 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: HE1PR0501MB2089 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/26/16 02:56, Greg KH wrote: > On Thu, Jun 09, 2016 at 08:40:32PM +0530, Bhuvanchandra DV wrote: >> From: Stefan Agner >> >> Currently the tx_empty callback only considers the Transmit Complete >> Flag (TC). The reference manual is not quite clear if the TC flag >> covers the TX FIFO too. Debug prints on real hardware have shown that >> from time to time the TC flag is asserted (indicating Transmitter >> idle) while there are still data in the TX FIFO. Hence, in this case >> the serial core will call the shutdown callback even though there are >> data remaining in the TX FIFO buffers. >> >> Avoid early shutdowns by considering the TX FIFO empty flag too. Also >> avoid theoretical race conditions between DMA and the driver by >> checking whether the TX DMA is in progress too. >> >> Signed-off-by: Stefan Agner >> --- >> drivers/tty/serial/fsl_lpuart.c | 14 ++++++++++++-- >> 1 file changed, 12 insertions(+), 2 deletions(-) > Why are you not signing off on patches that are flowing through you? > Please fix this up and resend the series, after breaking up the clock > change as asked. Okay > > thanks, > > greg k-h