From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Fri, 9 Dec 2016 10:36:57 +0100 Subject: [PATCH RFC] drm/sun4i: rgb: Add 5% tolerance to dot clock frequency check In-Reply-To: References: <20161124112231.4297-1-wens@csie.org> <20161206172911.z6sbjzgqv3vfcrfh@lukather> Message-ID: <20161209093657.jcalemg5xpumr2ma@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 07, 2016 at 10:26:25AM +0800, Chen-Yu Tsai wrote: > > Some panels require an exact frequency, some have a minimal frequency > > but no maximum, some have a maximum frequency but no minimal, and I > > guess most of them deviates by how much exactly they can take (and > > possibly can take more easily a higher frequency, but are less > > tolerant if you take a frequency lower than the nominal. > > > > And we cannot remove that check entirely, since some bridges will > > report out of range frequencies for higher modes that we know we > > cannot reach. > > I believe this should be handled by the bridge driver in the check > callback? This doesn't really have anything to do with the bridge itself, it's a limitation on the encoder. For all we know, the bridge might be able to operate at the higher resolutions without any issues if the encoder was able to. > The callback I'm changing is attached to the connector, which I > think doesn't get used if you have a bridge instead. And this only > checks the pre-registered display modes, such as those specified in > simple-panel or EDID. Geeee, I forgot to send that one (and thought I did)... I'll send that patch next week, but basically, I was creating a mode_valid hook at the encoder level, and moving the RGB mode_valid hook from the connector to the encoder (since it really is an encoder limitation). 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: 801 bytes Desc: not available URL: