From mboxrd@z Thu Jan 1 00:00:00 1970 From: Huang Shijie Subject: Re: [PATCH 1/5] serial: imx: remove unneeded imx_transmit_buffer() from imx_start_tx() Date: Mon, 12 May 2014 14:30:50 +0800 Message-ID: <53706A9A.6060707@freescale.com> References: <1399648788-26061-1-git-send-email-dean_jenkins@mentor.com> <1399648788-26061-2-git-send-email-dean_jenkins@mentor.com> <537042B5.2040600@freescale.com> <53706014.8010203@de.bosch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-by2on0054.outbound.protection.outlook.com ([207.46.100.54]:40926 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751058AbaELG2h (ORCPT ); Mon, 12 May 2014 02:28:37 -0400 In-Reply-To: <53706014.8010203@de.bosch.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Dirk Behme Cc: "dean_jenkins@mentor.com" , "gregkh@linuxfoundation.org" , "linux-serial@vger.kernel.org" , "s.hauer@pengutronix.de" , "linux-arm-kernel@lists.infradead.org" , "shawn.guo@freescale.com" =E4=BA=8E 2014=E5=B9=B405=E6=9C=8812=E6=97=A5 13:45, Dirk Behme =E5=86=99= =E9=81=93: > On 12.05.2014 05:40, Huang Shijie wrote: >> =E4=BA=8E 2014=E5=B9=B405=E6=9C=8809=E6=97=A5 23:19, dean_jenkins@me= ntor.com =E5=86=99=E9=81=93: >>> Use imx_start_tx() just to enable the TX interrupt. It's the job of= the >>> TX interrupt ISR to fill the transmit buffer, then. If the transmit= =20 >>> buffer From the Documentation/serial/driver, we can see: ----------------------------------------- start_tx(port) Start transmitting characters. ----------------------------------------- It tells us we can transmit data in the imx_start_tx. But this patch moves it to the interrupt handler, this patch makes the=20 interrupt handler do more jobs. >>> is empty, the TX interrupt should be executed as soon as the start_= tx() >>> enables the interrupt, so there is no reason for the extra >>> imx_transmit_buffer() call, here. Remove it. >> I don't know why this patch needed? >> What problem this patch fix or improve? > > As stated in the commit message, the call of imx_transmit_buffer()=20 > isn't needed there, so it can be removed. I.e. remove unneeded code. > > In the end, this cleans up the possible locking path, so that in the=20 > third patch the locking issue can be easily fixed. > The lock issue had been fixed already. Please try the latest linux-next= =2E see my comment in the third patch. thanks Huang Shijie -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: b32955@freescale.com (Huang Shijie) Date: Mon, 12 May 2014 14:30:50 +0800 Subject: [PATCH 1/5] serial: imx: remove unneeded imx_transmit_buffer() from imx_start_tx() In-Reply-To: <53706014.8010203@de.bosch.com> References: <1399648788-26061-1-git-send-email-dean_jenkins@mentor.com> <1399648788-26061-2-git-send-email-dean_jenkins@mentor.com> <537042B5.2040600@freescale.com> <53706014.8010203@de.bosch.com> Message-ID: <53706A9A.6060707@freescale.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ? 2014?05?12? 13:45, Dirk Behme ??: > On 12.05.2014 05:40, Huang Shijie wrote: >> ? 2014?05?09? 23:19, dean_jenkins at mentor.com ??: >>> Use imx_start_tx() just to enable the TX interrupt. It's the job of the >>> TX interrupt ISR to fill the transmit buffer, then. If the transmit >>> buffer From the Documentation/serial/driver, we can see: ----------------------------------------- start_tx(port) Start transmitting characters. ----------------------------------------- It tells us we can transmit data in the imx_start_tx. But this patch moves it to the interrupt handler, this patch makes the interrupt handler do more jobs. >>> is empty, the TX interrupt should be executed as soon as the start_tx() >>> enables the interrupt, so there is no reason for the extra >>> imx_transmit_buffer() call, here. Remove it. >> I don't know why this patch needed? >> What problem this patch fix or improve? > > As stated in the commit message, the call of imx_transmit_buffer() > isn't needed there, so it can be removed. I.e. remove unneeded code. > > In the end, this cleans up the possible locking path, so that in the > third patch the locking issue can be easily fixed. > The lock issue had been fixed already. Please try the latest linux-next. see my comment in the third patch. thanks Huang Shijie