On Tue, Oct 16, 2012 at 10:03:56AM -0600, Stephen Warren wrote: > On 10/16/2012 02:18 AM, Mark Zhang wrote: > > Hi, > > > > I've made this drm driver worked on Tegra 3(LVDS and HDMI both). > > But the code that Thierry > > hosts(git://gitorious.org/thierryreding/linux.git) doesn't work > > directly. If you build and run it, you'll get a white blank screen on > > Tegra 3. I didn't find the root cause but I think this is not caused by > > drm driver itself(maybe the PCIE codes?). The main symptom is: some > > regulators can't be inited all the time. I tried to build drm driver as > > kernel module, after kernel booted, modprobe the drm driver, and you'll > > find there are a lot of error prints like this: > > > > ========================================================= > > [ 21.383529] reg-fixed-voltage 1.regulator: Failed to find supply vin > > [ 21.390299] reg-fixed-voltage 1.regulator: Failed to register > > regulator: -517 > > [ 21.397645] platform 1.regulator: Driver reg-fixed-voltage requests > > probe deferral > > [ 21.405604] platform 2.regulator: Driver reg-fixed-voltage requests > > probe deferral > > ========================================================= > > This is normal; it's probe deferral. You'll find that those regulators > initialize correctly later. Hopefully tegra-drm handles this correctly, > and passes that error code through as the result of its probe. I presume those regulators are for the vdd and pll supplies of the HDMI output? Those should be properly handled by the tegra_hdmi_probe() function. Also the way tegra-drm works right now, unless all of the outputs are registered properly the DRM portion will never even be initialized. Thierry
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