From mboxrd@z Thu Jan 1 00:00:00 1970 From: jernej.skrabec@gmail.com (Jernej =?utf-8?B?xaBrcmFiZWM=?=) Date: Wed, 30 Nov 2016 21:41:26 +0100 Subject: [linux-sunxi] Re: [RFC PATCH] ARM: dts: sun8i: add simplefb node for H3 In-Reply-To: <20161130203724.a390595df0199ed19069f91d@free.fr> References: <20161130220324.3Kg4VPEw@smtp1m.mail.yandex.net> <2717236.xBNAaGdqdc@jernej-laptop> <20161130203724.a390595df0199ed19069f91d@free.fr> Message-ID: <185067972.ij8nq5Ea6J@jernej-laptop> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Dne sreda, 30. november 2016 ob 20:37:24 CET je Jean-Francois Moine napisal(a): > On Wed, 30 Nov 2016 20:14:11 +0100 > > Jernej ?krabec wrote: > > Dne ?etrtek, 01. december 2016 ob 03:03:14 CET je Icenowy Zheng napisal(a): > > > 2016?12?1? 02:49? Jernej Skrabec ??? > > > > > > > Hi Jean-Fran?ois, > > > > > > > > Dne sreda, 30. november 2016 10.35.08 UTC+1 je oseba Jean-Fran?ois > > > > Moine > > > > napisala: > > > >> On Tue, 29 Nov 2016 22:59:32 +0100 > > > >> > > > >> Maxime Ripard wrote: > > > >> > > > I'm still not sure which pipeline should I use. > > > >> > > > > > > >> > > > And, it seems that HDMI Slow Clock is not needed? > > > >> > > > > > > >> > > > (seems that it's only for EDID, but simplefb won't use EDID) > > > >> > > > > > >> > > So, I don't see how this may work. > > > >> > > How can the u-boot know the resolutions of the HDMI display > > > >> > > device? > > > >> > > > > > >> > > In other words: I have a new H3 board with the last u-boot and > > > >> > > kernel. > > > >> > > I plug my (rather old or brand new) HDMI display device. > > > >> > > After powering on the system, I hope to get something on the > > > >> > > screen. > > > >> > > How? > > > >> > > > > >> > If it works like the driver for the first display engine in U-Boot, > > > >> > it > > > >> > will use the preferred mode reported by the EDID, and will fallback > > > >> > to > > > >> > 1024x768 if it cannot access it. > > > >> > > > >> Icenowy wrote: "simplefb won't use EDID" > > > >> > > > >> Then, if it is like in the kernel, the 1024x768 mode is VGA. It does > > > >> not work with HDMI (different timings). > > > > > > > > U-Boot driver now accept any timings recommended by EDID. So far it > > > > was tested with at least following resolutions: > > > > - 1920x1080 @ 60 Hz > > > > - 1280x1024 @ 60 Hz > > > > - 1280x800 @ 60 Hz (slight clock difference) > > > > - 800x480 (not sure about frame rate) > > > > - 3840x2160 @ 30 Hz (4K) > > > > > > I tested on 1024x600 (If my memory is right, it's @ 60Hz) > > > > > > > and nobody complained so far. I'm pretty sure 1024x768 would work. > > Check the timings offered by the DRM core. I'm not really familiar with DRM code, but my Linux laptop happily works with 1024x768 @ 75 Hz and other non CEA resolutions through HDMI, so I guess it should be possible here too. Isn't function drm_add_edid_modes() designed exactly for that? Anyway, this is off topic for simplefb. Simplefb driver will just take over framebuffer set up by U-Boot with some additional info like width, height, pitch... It doesn't have to deal with HW directly. > > > > >> > Maybe it would be worth exchanging on the EDID code that has been > > > >> > done > > > >> > for the u-boot driver too, so that it can be fixed in your driver. > > > >> > > > >> The u-boot got my code, and, up to now, I could not fix the random or > > > >> permanent failures of EDID reading in some boards. > > > > > > > > I only have one OPi2, but as I said, EDID always worked for me. > > Happy guy! > > > > > The only > > > > code left from you is for DE2. HDMI stuff is basically copied from > > > > Rockhip > > > > driver (including EDID reading), TCON code is now reverted to the same > > > > as > > > > it is in sunxi_display.c. I think it is worth to take a look at EDID > > > > code > > > > and compare it. > > > > > > So is the TCON of DE 2.0 identical to the original TCON? > > > > > > If so, we should reuse sun4i-tcon ... > > > > Well, TCON is splitted in two parts (two base addresses), one for HDMI and > > one for TV. However, register offsets are same as before, so I guess > > driver reusage make sense. I think that there are few additional > > registers, but they can be ignored for simplefb. > > The TCON1 of the H3 is not usable (no ckock). Analog TV has its own > clock and I/O area. > True, H3 user manual can be misleading sometimes. But this doesn't change the fact that TCON0 has same register offsets with same meaning. > -- > Ken ar c'henta? | ** Breizh ha Linux atav! ** > Jef | http://moinejf.free.fr/