On Thu, 21 Aug 2014 11:41:59 +0200 Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, 21 Aug 2014 11:04:07 +0200 > Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > > > On Thu, Aug 21, 2014 at 10:37:06AM +0200, Boris BREZILLON wrote: > > > Hi Ludovic, > > > > > > On Thu, 21 Aug 2014 10:16:19 +0200 > > > Ludovic Desroches <ludovic.desroches@xxxxxxxxx> wrote: > > > > > > > Hi Boris, > > > > > > > > You can add > > > > > > > > Tested-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx> > > > > > > Thanks for testing this driver. > > > > > > > > > > > Only one issue but not related to your patches, you can't display > > > > quickly the bootup logo since the panel detection takes too much > > > > time. > > > > > > Yes, actually this is related to the device probe order: the > > > hlcdc-display-controller device is probed before the simple-panel, thus > > > nothing is detected on the RGB connector (I use of_drm_find_panel to > > > check for panel availability) when the display controller is > > > instantiated. I rely on the default polling infrastructure provided by > > > the DRM/KMS framework which polls for a new connector every 10s, and > > > this is far more than you kernel boot time. > > > > > > Do anyone see a solution to reduce this delay (without changing the > > > polling interval). I thought we could add a notifier infrastructure to > > > the DRM panel framework, but I'm not sure this is how you want things > > > done... > > > > Other drivers return -EPROBE_DEFER when a panel hasn't been registered > > yet. This will automatically take care of ordering things in a way that > > DRM/KMS will only be initialized after the panel has been probed. > > Actually I'd like to avoid doing this with a deferred probe, because, > AFAIU, the remote endpoint is not tightly linked with the display > controller driver (I mean the display controller can still be > initialized without having a display connected on it). > Moreover the atmel dev kit I'm using has an HDMI bridge connected on > the same RGB connector and I'd like to use it in a near future. > Returning -EPROBE_DEFER in case of several devices connected on the > same connector implies that I'll have to wait for all the remote > end-points to be available before my display controller could be > instantiated. > > While this could be acceptable when all drivers are statically linked > in the kernel, it might be problematic when you're using modules, > meaning that you won't be able to display anything on your LCD panel > until your HDMI bridge module has been loaded. > > > That > > will still cause some delay before everything gets set up, but hopefully > > less than what you're seeing now. There's also another thread where this > > is being discussed because deferred probing is causing "unacceptable" > > delays as well. > > Could you point this thread out to me please ? Sorry, I didn't check my emails before asking this :-). > > Best Regards, > > Boris > -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
