From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Thumshirn Subject: Re: [PATCH] tty: serial: men_z135_uart: Fix driver for changes in hardware Date: Wed, 10 Sep 2014 08:07:24 +0200 Message-ID: <20140910060723.GA3525@jtlinux> References: <1409229140-14407-1-git-send-email-johannes.thumshirn@men.de> <20140908231733.GB23907@kroah.com> <20140909055615.GA10306@jtlinux> <20140910002635.GA2189@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Received: from mail1.bemta5.messagelabs.com ([195.245.231.140]:34551 "EHLO mail1.bemta5.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978AbaIJGKK (ORCPT ); Wed, 10 Sep 2014 02:10:10 -0400 Content-Disposition: inline In-Reply-To: <20140910002635.GA2189@kroah.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Greg Kroah-Hartman Cc: Johannes Thumshirn , Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org On Tue, Sep 09, 2014 at 05:26:35PM -0700, Greg Kroah-Hartman wrote: > On Tue, Sep 09, 2014 at 07:56:15AM +0200, Johannes Thumshirn wrote: > > On Mon, Sep 08, 2014 at 04:17:33PM -0700, Greg Kroah-Hartman wrote: > > > > > > > > @@ -118,6 +117,10 @@ static int align; > > > > module_param(align, int, S_IRUGO); > > > > MODULE_PARM_DESC(align, "Keep hardware FIFO write pointer aligned, default 0"); > > > > > > > > +static int rx_timeout; > > > > +module_param(rx_timeout, uint, S_IRUGO); > > > > +MODULE_PARM_DESC(rx_timeout, "RX timeout"); > > > > > > Why add a module parameter? Who will know to set this? And to what > > > value? > > > > > > > There will be a user manual describing the parameter. It's like the rxlvl and > > txlvl parameters, you'll have to read the manual if you need other values than > > the default ones. > > Ugh, but module parameters are for all devices in the system of this > type, which is why we try not to have them at all anymore. > > And I don't like the other module parameters either :( > > But it's an odd-one-off driver, I guess we can live... Just for my information, what would be the correct way to do these kinds of hardware specific settings? Sysfs? Debugfs? Custom ioctl()s (no struct file_operations, so probably not)? I guess we (and others) have a lot hardware that can be tweaked some way other than what the framework supports and if module parameters aren't the way to go I there must be some other way to configure this. > > > > And what about this driver working on old hardware, didn't you just > > > break this? > > > > > > > No. Currently the hardware is in a testing stage at only one customer and it is > > an IP-Core inside a FPGA, so it can be (and already is) updated. So we can be > > save to assume this is O.K. > > Ok, can you please resend this, it's gone from my queue now. O.K. On the way. Thanks, Johannes