Hi Eugeniu On Fri, Jun 05, 2020 at 03:41:24PM +0200, Eugeniu Rosca wrote: > Hi Jacopo, > > On Fri, Jun 05, 2020 at 03:29:00PM +0200, Jacopo Mondi wrote: > > On Wed, May 27, 2020 at 09:15:55AM +0200, Eugeniu Rosca wrote: > > > Could you kindly share the cross compilation steps for your kmsxx fork? > > > > I usually build it on the target :) > > Interesting approach. With ARM getting more and more potent, why not? :) > For 'small' utilities like kmsxx it's doable > > > > > Just out of curiosity, have you ever tried to pull the display's HDMI > > > cable while reading from CM2_LUT_TBL? > > > > Ahem, not really :) Did I get you right, you mean disconnecting the > > HDMI cable from the board ? > > Right. > So, no, I have not tried. Do you see any intersting failure with the mainline version ? > > > > > > At least with the out-of-tree CMM implementation [*], this sends the > > > R-Car3 reference targets into an unrecoverable freeze, with no lockup > > > reported by the kernel (i.e. looks like an serious HW issue). > > > > > > > > > > > CMM functionalities are retained between suspend/resume cycles (tested with > > > > suspend-to-idle) without requiring a re-programming of the LUT tables. > > > > > > Hmm. Is this backed up by any statement in the HW User's manual? > > > This comes in contrast with the original Renesas CMM implementation [**] > > > which does make use of suspend (where the freeze actually happens). > > > > > > Can we infer, based on your statement, that we could also get rid of > > > the suspend callback in [**]? > > > > As Geert (thanks) explained what I've tested with is suspend-to-idle, > > which retains the state of the LUT tables (and I assume other > > not-yet-implemented CMM features, like CLU). I recall the out-of-tree > > driver has suspend/resume routines but I never really tested that. > > I see. JFYI, there is a flaw in the suspend handling in the out-of-tree > CMM patch [*], which renders the SoC unresponsive on HDMI hotplug. The > fix is currently under review. Hopefully it will make its way to [*] > in the nearest future. Just to keep in mind for the moment when CMM > s2ram will become a mainline feature. Thanks, let's keep this in mind. Next week I'll run a few tests again with s2ram and will get back to you. Thanks j > > > > > > > [*] https://github.com/renesas-rcar/du_cmm > > > [**] https://github.com/renesas-rcar/du_cmm/blob/c393ed49834bdbc/meta-rcar-gen3/recipes-kernel/linux/linux-renesas/0001-drm-rcar-du-Add-DU-CMM-support.patch#L1912 > > -- > Best regards, > Eugeniu Rosca
