From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [RFC PATCH] drivers: ata: Read Rx water mark value from device-tree Date: Mon, 22 Feb 2016 16:19:39 +0100 Message-ID: <18251200.Xfr10N5eWq@wuerfel> References: <1455974302-7082-1-git-send-email-anuragku@xilinx.com> <28916176.WDrPajhOPa@wuerfel> <3802E9A6666DF54886E2B9CBF743BA9825E00BD4@XAP-PVEXMBX01.xlnx.xilinx.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <3802E9A6666DF54886E2B9CBF743BA9825E00BD4@XAP-PVEXMBX01.xlnx.xilinx.com> Sender: linux-ide-owner@vger.kernel.org To: Anurag Kumar Vulisha Cc: "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "tj@kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-ide@vger.kernel.org" , Anirudha Sarangi , Srikanth Vemula , Punnaiah Choudary Kalluri List-Id: devicetree@vger.kernel.org On Monday 22 February 2016 10:53:11 Anurag Kumar Vulisha wrote: > > > > > > > How would a hardware integrator know which value is right for a particular > > SoC? > > > > Could it be keyed off the hardware ID? Could the bootloader perhaps set an > > appropriate value in the AHCI_VEND_PTC register at boot time and the driver > > read the initial value from it? > > > > From the description, it sounds like this is a policy decision rather than > > hardware description, and shouldn't really be in here. > > > > Thanks for reviewing the patch. Can I use module_param() for this watermark instead of reading it from devicetree or > doing it in bootloader. In bootloader we are initializing serdes controller for high speed devices. As a part of this initialization > we will be reseting all the high speed pheripherals which are using serdes, so SATA will also get resetted. Because of this > reason, can I use module_param() for Rxwatermark value instead? > I don't know what is appropriate because I have no idea what Rxwatermark is good for. Can you try describing why we can't just set it to the correct value for everyone automatically? Arnd