From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= Subject: Re: [PATCH 0/3] drm: tinydrm driver for adafruit PiTFT 3.5" touchscreen Date: Wed, 31 Oct 2018 17:27:57 +0100 Message-ID: <0566ac0e-6060-6b46-b75a-32c63ef9dbe2@tronnes.org> References: <20181024184313.2967-1-eric@anholt.net> <87h8harnv4.fsf@anholt.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87h8harnv4.fsf@anholt.net> Sender: linux-kernel-owner@vger.kernel.org To: Eric Anholt , dri-devel@lists.freedesktop.org, Rob Herring , Mark Rutland , devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Heiner Kallweit List-Id: dri-devel@lists.freedesktop.org Den 25.10.2018 18.29, skrev Eric Anholt: > Eric Anholt writes: > >> I was going to start working on making the vc4 driver work with >> tinydrm panels, but it turned out tinydrm didn't have the panel I had >> previously bought. So, last night I ported the fbtft staging >> driver over to DRM. >> >> It seems to work (with DT at >> https://github.com/anholt/linux/commits/drm-misc-next-hx8357d) -- >> fbdev works great including rotated, and so does modetest. However, >> when X11 comes up at 16bpp, I get: >> >> https://photos.app.goo.gl/8tuhzPFFoDGamEfk8 >> >> If I have tinydrm set a preferred bpp of 24, X looks great. Noralf, >> any ideas? > Also, with these patches and the format modifier patch I just sent, mesa > with vc4 is now working with this driver on this branch: > > https://gitlab.freedesktop.org/anholt/mesa/commits/kmsro > > Now I wonder how we can improve performance of the SPI updates. I just remembered that tinydrm does a full flush on page flips. And if the dirtyfb ioctl is also used you end up with two flushes. This could explain bad performance. I have been waiting for the dirtyfb through atomic work to come to fruition, but nothing merged yet. That would give dirty tracking on page flips. Noralf.