linux-kernel - Re: [RFC PATCH 0/3] staging: remove fbdev drivers

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Message-ID: <1481158879.26959.41.camel@kernel.crashing.org>
Date:   Thu, 08 Dec 2016 12:01:19 +1100
From:   Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:     Tomi Valkeinen <tomi.valkeinen@...com>,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Noralf Trønnes <noralf@...nnes.org>,
        Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        Teddy Wang <teddy.wang@...iconmotion.com>,
        Arnaud Patard <arnaud.patard@...-net.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 0/3] staging: remove fbdev drivers

On Wed, 2016-11-23 at 10:03 +0200, Tomi Valkeinen wrote:
> Hi,
> 
> Since the fbdev framework is in maintenance mode and all new display drivers
> should be made with the DRM framework, remove the fbdev drivers from staging.
> 
> Note: the patches are created with git format-patch -D, so they can't be
> applied. Only for review.

I missed the discussion where this decision was made, I admit I am
unimpressed by it.

DRM drivers don't strike me as suitable for small/slow cores with dumb
framebuffers or simple 2D only accel, such as the one found in the ASpeed
BMCs.

With drmfb you basically have to shadow everything into memory & copy
over everything, and locks you out of simple 2D accel. For a simple text
console the result is orders of magnitude slower and memory hungry than
a simple fbdev.

At least that was the case last I looked at the DRM stuff with Dave,
maybe things have changed... 

Not everything has a powerful 3D GPU.

Ben.