PL111 regression in v4.19-rc1

[Noralf Trønnes]

Hi Linus,

Den 27.08.2018 14.12, skrev Linus Walleij:
> Hi folks,
>
> I'm seeing this on all PL111 systems (several ARM reference
> designs and Nomadik) with v4.19-rc1:
>
> [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 ../include/linux/dma-mapping.h:516
> drm_gem_cma_create+0x13c/0x158
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper Not tainted 4.18.0+ #135
> Hardware name: ARM-Versatile (Device Tree Support)
> [<c001c4e0>] (unwind_backtrace) from [<c0019198>] (show_stack+0x10/0x14)
> [<c0019198>] (show_stack) from [<c0024528>] (__warn+0xcc/0xf4)
> [<c0024528>] (__warn) from [<c0024664>] (warn_slowpath_null+0x3c/0x48)
> [<c0024664>] (warn_slowpath_null) from [<c0259710>]
> (drm_gem_cma_create+0x13c/0x158)
> [<c0259710>] (drm_gem_cma_create) from [<c0234700>]
> (drm_fbdev_cma_create+0x58/0x248)
> [<c0234700>] (drm_fbdev_cma_create) from [<c0233d3c>]
> (__drm_fb_helper_initial_config_and_unlock+0x1c8/0x450)
> [<c0233d3c>] (__drm_fb_helper_initial_config_and_unlock) from
> [<c023450c>] (drm_fb_cma_fbdev_init_with_funcs+0x8c/0x114)
> [<c023450c>] (drm_fb_cma_fbdev_init_with_funcs) from [<c025d23c>]
> (pl111_amba_probe+0x3c8/0x4a4)
> [<c025d23c>] (pl111_amba_probe) from [<c01f3c64>] (amba_probe+0xd8/0x154)
> [<c01f3c64>] (amba_probe) from [<c02637e4>] (driver_probe_device+0x25c/0x310)
> [<c02637e4>] (driver_probe_device) from [<c0263968>] (__driver_attach+0xd0/0xd4)
> [<c0263968>] (__driver_attach) from [<c0261b30>] (bus_for_each_dev+0x70/0xb4)
> [<c0261b30>] (bus_for_each_dev) from [<c0262c74>] (bus_add_driver+0x170/0x204)
> [<c0262c74>] (bus_add_driver) from [<c0264278>] (driver_register+0x74/0x108)
> [<c0264278>] (driver_register) from [<c000abf8>] (do_one_initcall+0x48/0x1a0)
> [<c000abf8>] (do_one_initcall) from [<c04fedc0>]
> (kernel_init_freeable+0x104/0x1c4)
> [<c04fedc0>] (kernel_init_freeable) from [<c03e0f04>] (kernel_init+0x8/0xf0)
> [<c03e0f04>] (kernel_init) from [<c00090e0>] (ret_from_fork+0x14/0x34)
> Exception stack(0xc781ffb0 to 0xc781fff8)
> ffa0:                                     00000000 00000000 00000000 00000000
> ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> ffe0: 00000000 00000000 00000000 00000000 00000013 00000000
> ---[ end trace 63124893aa47fae0 ]---
> drm-clcd-pl111 dev:20: coherent DMA mask is unset
> drm-clcd-pl111 dev:20: [drm:drm_fb_cma_fbdev_init_with_funcs] *ERROR*
> Failed to set fbdev configuration.
> [drm] Initialized pl111 1.0.0 20170317 for dev:20 on minor 0
>
> I am trying to bisect but it is really painful because the kernel simply
> does not compile on a lot of bisect points :(

This is one suspect: 894a677f4b3e
drm/cma-helper: Use the generic fbdev emulation

Noralf.

> Any hints? Eric is PL111 working for you?
>
> Yours,
> Linus Walleij