From mboxrd@z Thu Jan 1 00:00:00 1970 From: Flavio Suligoi Subject: RE: [PATCH 1/1] spi: pxa2xx: add driver enabling message Date: Wed, 10 Apr 2019 12:01:15 +0000 Message-ID: <6953cafeb6bc4367842f37f567bb893f@asem.it> References: <1554736964-6058-1-git-send-email-f.suligoi@asem.it> <20190410103250.GF6106@sirena.org.uk> <20190410115431.GO6106@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Cc: Daniel Mack , Haojian Zhuang , Robert Jarzmik , "linux-arm-kernel@lists.infradead.org" , "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" To: Mark Brown Return-path: In-Reply-To: <20190410115431.GO6106@sirena.org.uk> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org > On Wed, Apr 10, 2019 at 11:47:43AM +0000, Flavio Suligoi wrote: > > > You have right about to avoid too many boot messages, > > but in this case, using an x86 machine and with > > the spi-pxa2xx in DMA mode, so without the message: > > > "no DMA channels available, using PIO", > > > there is absolutely no indication about the existence > > of the SPI master controller. > > It's totally fine to not have a boot print for the device, the best way > to find devices if you need them is to look in sysfs anyway. Ok > > The second reason is about the DMA/PIO mode indication. > > With the board I'm using, sometimes the spi-pxa2xx driver can't allocate > > a DMA channel and works in PIO mode. > > > So, with the advice of Jarkko, I think that a valid solution could be: > > > 1) remove the "no DMA channels available, using PIO" message > > 2) add a new message with the indications of: > > - controller mode (slave or master) > > - transfer mode (DMA or PIO) > > > What do you think about this? > > If the system is randomly failing to assign a DMA channel when it should > then shouldn't we just fix that? A print which is presumably intended > to prompt the user to reboot to try to get things working doesn't seem > like a good solution. Right, I'm just fix the DMA problem (I'm preparing a patch about this) Flavio