Hello everybody! I am fighting to enable ldb in Linux 4.9.7. In barebox the SAME device-tree is modified by barebox to enable/disable the ldb or hdmi depending on what is found. During Linux bootup with HDMI only, it works with no hassle. If booting with ldb it does not start the ldb driver registration due to a panel/bridge missing. In the config of linux kernel I have (as imx_v6_v7_defconfig) all drm and simple panel enabled. What is missing??? Best regards, Gianluca -------- Forwarded Message -------- Subject: Barebox 2017.02 works great but no Linux Framebuffer... :-/ Date: Mon, 20 Feb 2017 16:36:06 +0100 From: gianluca To: Sascha Hauer Hello Sascha, During last week I was able to activate/deactivate the hdmi and ldb nodes from internal device-tree of Barebox and everything is working great. Now I would like to boot up with the kernel 4.9.7 with the following commandline but it fails. The kernelcmd line is: > console=ttymxc2,115200 rootwait noswap ip=none noinitrd rootfstype=nilfs2 root=/dev/mmcblk1p3 fec.macaddr=0x7a,0x3f,0x03,0xe3,0xa2,0xff system_rev=0xe3600000 system_serialnr=0x00000000 lcd_type=am1280800n3tz fastboot quiet loglevel=3 console=tty0 video=mxcfb0:dev=ldb,if=RGB24,bpp=32 fbmem=32M vmalloc=400M The problem is the ldb (imx-ldb.c you wrote in kernel drivers/gpu/drm/imx...). It fails with the following error: > [ 7.526349] imx-ldb 2000000.aips-bus:ldb@020e0008: panel/bridge not found: /panel -- > [ 7.526369] imx-drm display-subsystem: failed to bind 2000000.aips-bus:ldb@020e0008 (ops 0xc097aaa0): -517 > [ 7.526785] imx-drm display-subsystem: master bind failed: -517 The device-tree is attached. The device tree is the same as Barebox (it has only an #included commented out). Both hdmi and ldb nodes are initially left "disabled" then barebox enable the node corresponding to the hardware found (i.e. it changes the status to "okay") In barebox everything is working. In linux NOT. What is exactly a 'channel->bridge' and 'channel->panel' in device-tree therminology? Barebox is working without it, so I suppose it was working in Linux kernel too... Regards, -- Eurek s.r.l. | Electronic Engineering | http://www.eurek.it via Celletta 8/B, 40026 Imola, Italy | Phone: +39-(0)542-609120 p.iva 00690621206 - c.f. 04020030377 | Fax: +39-(0)542-609212