From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Airlie Subject: Re: [PATCH 1/2] drm: allow drivers to provide their own EDID fetching routine Date: Wed, 21 Jul 2010 09:35:38 +1000 Message-ID: <1279668938.337.7.camel@clockmaker-el6> References: <20100720154417.32091370@virtuousgeek.org> <1279666470.337.5.camel@clockmaker-el6> <20100720160547.5e73889c@virtuousgeek.org> <1279668474.337.6.camel@clockmaker-el6> <20100720163439.6c69e16e@virtuousgeek.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100720163439.6c69e16e@virtuousgeek.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Jesse Barnes Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Tue, 2010-07-20 at 16:34 -0700, Jesse Barnes wrote: > On Wed, 21 Jul 2010 09:27:54 +1000 > Dave Airlie wrote: > > > On Tue, 2010-07-20 at 16:05 -0700, Jesse Barnes wrote: > > > On Wed, 21 Jul 2010 08:54:30 +1000 > > > Dave Airlie wrote: > > > > > > > On Tue, 2010-07-20 at 15:44 -0700, Jesse Barnes wrote: > > > > > Make drm_edid_read take a new argument, edid_read, to allow drivers to > > > > > provide their own EDID fetch routine. Export the bit banging DDC over > > > > > i2c version of the EDID fetching routine and make the drivers use it. > > > > > This sets the stage for GMBUS support in the Intel driver. > > > > > > > > > > > > > I think this needs some rework. > > > > > > > > You might want to checkout what the radeon driver does for hw i2c > > > > engine. You should set up your own i2c hw handlers and use those instead > > > > of bypassing the i2c stack. GMBUS is just another i2c hw block. > > > > > > I'll check it out, but I don't see what using the i2c stack buys us > > > here except for obfuscation... > > > > > > > You'll want to use GMBUS for SDVO at some point in the future, or > > something else, or you'll want to expose it to userspace for DDC/CI > > users. Lots of reasons, its not obfuscation at all, what you are doing > > is dodgy shortcuts. > > Using it for SDVO and other things means some other changes to the > GMBUS code unfortunately. Still not seeing how using i2c makes > userspace exposure or SDVO usage easier, but I don't care, I'll switch > it around to use i2c core code. > You can expose /dev/i2c devices properly to userspace, you can't do that with the code you proposed. Dave.