On Mon, Aug 21, 2017 at 03:45:21PM +0100, Vladimir Murzin wrote: > On 10/08/17 13:15, Vladimir Murzin wrote: > > On 26/07/17 11:27, Russell King - ARM Linux wrote: > >> I suspect the above failure is down to either (a) not having enough > >> memory available to allocate a 1920x1080 frame buffer, or (b) not > >> (yet) being able to program the hdlcd pixel clock for this platform, > >> which is currently hard-coded in DT at 23.75MHz. > > > > Given it is NOMMU it is likely (a). Usually, tweaking FORCE_MAX_ZONEORDER > > helped me in such cases. > > Ok, with CONFIG_FORCE_MAX_ZONEORDER=12 I see > > [ 5.242423] [drm] found ARM HDLCD version r0p0 > [ 5.493835] tda998x 2-0070: found TDA19988 > [ 5.527771] hdlcd 40205000.hdlcd: bound 2-0070 (ops 0x1470f8) > [ 5.535819] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). > [ 5.543478] [drm] No driver support for vblank timestamp query. > [ 7.443189] hdlcd 40205000.hdlcd: fb0: frame buffer device > [ 7.501975] [drm] Initialized hdlcd 1.0.0 20151021 for 40205000.hdlcd on minor 0 > > when display is connected. > > To make fb-test [1] happy I had to apply following diff: > > diff --git a/drivers/gpu/drm/arm/Kconfig b/drivers/gpu/drm/arm/Kconfig > index 9a18e1b..d4cb1b1 100644 > --- a/drivers/gpu/drm/arm/Kconfig > +++ b/drivers/gpu/drm/arm/Kconfig > @@ -10,6 +10,7 @@ config DRM_HDLCD > select DRM_ARM > select DRM_KMS_HELPER > select DRM_KMS_CMA_HELPER > + select FB_PROVIDE_GET_FB_UNMAPPED_AREA if !MMU > help > Choose this option if you have an ARM High Definition Colour LCD > controller. > > (The only user of FB_PROVIDE_GET_FB_UNMAPPED_AREA is NOMMU only drivers/gpu/drm/stm/) > > However, I do not see anything on the screen. I'm probably missing something > obvious, so if you have an idea, please let me know and I can test the patch. Do you have fbdev/fbcon enabled? If not, then you need some userspace that makes use of the DRM interface. I usually play with the tests from libdrm, you can start with modetest. Best regards, Liviu > > [1] https://github.com/prpplague/fb-test-app.git > > Thanks > Vladimir > > > > > Cheers > > Vladimir > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ -- 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
