From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Mon, 29 Jan 2018 13:53:41 +0100 Subject: [PATCH 2/2] drm/sun4i: Handle DRM_MODE_FLAG_**SYNC_POSITIVE correctly In-Reply-To: <18ec71dc-a785-a771-76d4-176d95032c97@micronovasrl.com> References: <1516474221-114596-1-git-send-email-giulio.benetti@micronovasrl.com> <1516474221-114596-2-git-send-email-giulio.benetti@micronovasrl.com> <20180122085112.7xo2t3x5ag4k2kpl@flea.lan> <59f7b542-3b1d-ff62-e290-37c47f4075ff@micronovasrl.com> <9929d894-53c3-a7e9-a328-a00cfc1ef546@micronovasrl.com> <20180125152117.qikemrwl7f35ssjg@flea.lan> <20180126145608.5s6c6ltpvrko7iyv@flea.lan> <18ec71dc-a785-a771-76d4-176d95032c97@micronovasrl.com> Message-ID: <20180129125341.elup47ymedzxornn@flea.lan> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Fri, Jan 26, 2018 at 04:55:54PM +0100, Giulio Benetti wrote: > > > > > It behaves the same way as A20, so as I mean IO polarity, > > > > > all signals(except D0-D23), are inverted. > > > > > For A33 I've used A33-OLinuXino. > > > > > For A20 our LiNova1. > > > > > > > > Indeed, HSYNC and VSYNC look inverted. > > > > > > Yes, so they should be inverted inside the driver. > > > > Yep. And the LCD panels used on our boards as well in order to avoid > > any breakages. > > Can you provide a list? > Or is there a way I can find it on my own? > I can create a whole patch-set providing this too on panel-simple.c > Ok? Grepping through the DT, it seems like there's only the A13 q8 tablet and the SinA33. The former uses simple-panel, the latter a custom panel driver. > > > A little out of thread but: > > > I'd like to send one for u-boot too, > > > but this means also to modify every sunxi "sync:3" to "sync:0" and > > > vice-versa. > > > > > > What do you think? > > > > That it's going to be a nightmare... We've advertised since the very > > beginning something, and we're about to break it. I'm not sure we want > > to do that. > > I can take care about that. > But I also think that a lot of displays work because they use only DE-mode, > almost ignoring HSync and VSync signals(HV-mode). > > In any case I have to produce these patches because of my company's board > based on A20 and A33, and modify defconfig according to it. > The only technical nightmare I see is to produce a commit for every > defconfig to be modified and copy-paste che commit-log substituing board > name(1-2 days of work). > Problem is testing, but we're speaking about something that probably was > badly working, but you couldn't see it on display. > So I think this is only an improvement at the end. It really is a separate discussion, but you would also need to fix all the environments everywhere, which is simply not feasible. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: not available URL: