Fwd: Barebox 2017.02 works great but no Linux Framebuffer... :-/

[gianluca]

On 02/21/2017 02:04 PM, gianluca wrote:
>
> 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???
>

At the moment I can clearly state that (as kernel 4.9.7):

in the imx-ldb.c (line 711) in the function imx_ldb_bind() the error is 
the channel->panel AND channel->bridge ARE both NULL.

The struct device_node *ep = of_graph_get_endpoint_by_regs(child, 
imx_ldb->lvds_mux ? 4 : 2, -1) is not null and the remote struct 
device_node as full name has: /panel.

This look suspicious to me as I am expecting a full_name as: 
/soc/node/this/is/a/complete/name/panel stuff.

Anyway this issue is preventing to continue and registering a frame 
buffer on the lvds channel.

Can anybody point me in the right direction? In the next few moments I 
will try to diff the device-tree passed from barebox to linux kernel and 
the device-tree expected.

Hold on... ;-)

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 <gianlucarenzi at eurekelettronica.it>
> To: Sascha Hauer <s.hauer at pengutronix.de>
>
> 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 at 020e0008: panel/bridge not
>> found: /panel --
>> [    7.526369] imx-drm display-subsystem: failed to bind
>> 2000000.aips-bus:ldb at 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,
>
>
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> barebox at lists.infradead.org
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>


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