From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: exynos4412: powerdomain issues with HDMI PHY and VP Date: Tue, 27 May 2014 09:49:50 -0700 Message-ID: <7hwqd79nf5.fsf@paris.lan> References: <538104FF.7070601@gmx.net> <53810E0D.5010802@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:38485 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752639AbaE0Qtw (ORCPT ); Tue, 27 May 2014 12:49:52 -0400 Received: by mail-pa0-f46.google.com with SMTP id kq14so9429540pab.19 for ; Tue, 27 May 2014 09:49:52 -0700 (PDT) In-Reply-To: <53810E0D.5010802@gmail.com> (Tomasz Figa's message of "Sat, 24 May 2014 23:24:29 +0200") Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Tomasz Figa Cc: Tobias Jakobi , linux-samsung-soc@vger.kernel.org, Inki Dae , arun.kk@samsung.com, Tomasz Stanislawski , "Rafael J. Wysocki" , Ulf Hansson , Marek Szyprowski Tomasz Figa writes: > Hi Tobias, > > First of all, big thanks for investigating this issue. Hopefully we can > have it fixed in upstream soon. > > I've added Tomasz Stanislawski to CC list, as he's been doing some work > to enable HDMI support on Exynos4 using Exynos DRM. > > On 24.05.2014 22:45, Tobias Jakobi wrote: >> Hello, >> >> I'm still working on getting HDMI output on my ODROID-X2 board (based on >> Exynos4412 Prime) working. My tree is a 3.15-rc6 with some patches on >> top to get it boot on the board. >> >> You can find the tree here: >> https://github.com/tobiasjakobi/linux-odroid/commits/odroid-3.15.y >> >> Here is the DTS: >> https://github.com/tobiasjakobi/linux-odroid/blob/odroid-3.15.y/arch/arm/boot/dts/exynos4412-odroidx2.dts >> >> I encountered two issues with powerdomains. On related to HDMI PHY and >> the other one related to the VP (video processor). >> >> The pd the mixer is in, is currently set to pd_tv. I can't seem to >> specify multiple powerdomains for one device. However the PHY seems to >> need both TV and LCD0 pd to function properly. > > We've discovered this issue too. Unfortunately the Linux implementation > of generic power domain core (genpd) doesn't support multiple power > domains per device, so we ended up with a hack in our internal tree. > > Generic power domain bindings aren't going to help too much, because > even though they account for this, the implementation will use only the > first domain. > > I have CC'ed Rafael, Kevin and Ulf, as they might have some ideas how to > solve this. Hmm, this seems a bit strange. How is this implemented in hardware? It seems rather unlikely that the same IP block is getting power from two different power rails. So I don't think what you really want is to have the device modeled in 2 power domains. Rather, I suspect there's some functional dependency going on that's not directly a function of the power domain itself. Taking a wild shot in the dark, it wouldn't be too surprising if the IP block in question depends on a clock coming from a device in another power domain? Since this sounds display related, is the pixel clock required coming from an IP block in the other power domain? If it's something like a clock dependency, then that needs to be modeled so what when the clock is enabled, the power domain containg the device providing that clock cannot be shut down. Kevin