imxdrm issue on Hummingboard with LVDS enabled

[Fabio Estevam]

Hi Russell,

On Sun, Feb 12, 2017 at 11:18 AM, Russell King - ARM Linux
<linux at armlinux.org.uk> wrote:
> Hi,
>
> Here's another issue with imxdrm.  I got this while trying to reproduce
> Dan's problem by enabling the lvds output using the patch below
> originally from Fabio, but updated a bit.  This doesn't occur if I leave
> LVDS disabled.
>
> The taint is due to the IMX capture modules from Steve, who chose to put
> his code in drivers/staging/media rather than drivers/media.  However,
> the last module to make the capture stuff active (imx-csi) which interfaces
> the drivers/gpu/ipu-v3 code with the capture code has not been loaded.
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 1049 at /home/rmk/git/linux-rmk/drivers/gpu/drm/drm_atomic_helper.c:1149 drm_atomic_helper_wait_for_vblanks+0x218/0x224
> [CRTC:29] vblank wait timed out

I am getting the same warning when trying to add HDMI support on
imx6sx-udoo-neo board via TDA19988:

[drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[drm] No driver support for vblank timestamp query.
tda998x 2-0070: Falling back to first CRTC
random: fast init done
tda998x 2-0070: found TDA19988
mxsfb 2220000.lcdif: bound 2-0070 (ops tda998x_ops)
[drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[drm] No driver support for vblank timestamp query.
 ------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/gpu/drm/drm_atomic_helper.c:1149
drm_atomic_helper_wait_for_vblanks+00
[CRTC:26] vblank wait timed out
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.10.0-rc7-00034-g2217172 #155
Hardware name: Freescale i.MX6 SoloX (Device Tree)
Backtrace:
[<c010c338>] (dump_backtrace) from [<c010c5e4>] (show_stack+0x18/0x1c)
r7:00000000 r6:60000013 r5:00000000 r4:c0e29258
[<c010c5cc>] (show_stack) from [<c04004e0>] (dump_stack+0xb4/0xe8)
[<c040042c>] (dump_stack) from [<c012590c>] (__warn+0xd8/0x104)
r9:c04d63ac r8:0000047d r7:00000009 r6:c0c1f2b4 r5:00000000 r4:ef05f8c8
[<c0125834>] (__warn) from [<c0125974>] (warn_slowpath_fmt+0x3c/0x44)
r9:ef350000 r8:ef037028 r7:00000000 r6:ef3bd600 r5:ef3d2c00 r4:c0c1f3d0
[<c012593c>] (warn_slowpath_fmt) from [<c04d63ac>]
(drm_atomic_helper_wait_for_vblanks+0x230/0x240)
r3:0000001a r2:c0c1f3d0
r4:00000000
[<c04d617c>] (drm_atomic_helper_wait_for_vblanks) from [<c04d64bc>]
(drm_atomic_helper_commit_tail+0x50)
r10:00000001 r9:ef3cd100 r8:ef350484 r7:ef350000 r6:00000000 r5:ef350000
r4:ef3d2c00
....

I haven't had a chance to debug this yet. If anyone makes any
progress, please keep me on Cc.

Thanks