[Letux-kernel] Debugging 4.11-rc6 on GTA04

H. Nikolaus Schaller hns at goldelico.com
Thu Apr 13 17:56:08 CEST 2017

Hi Andreas,

> Am 12.04.2017 um 07:07 schrieb Andreas Kemnade <andreas at kemnade.info>:

--- snip ---

>> Maybe mainline has another bug. Or our latest patches trigger that in 4.11
>> but not in 4.10.
> Display problems seem to start with this patch:
> 897145d0c7010b4e07fa9bc674b1dfb9a2c6fff9 is the first bad commit
> commit 897145d0c7010b4e07fa9bc674b1dfb9a2c6fff9
> Author: Jyri Sarha <jsarha at ti.com>
> Date:   Fri Jan 27 12:04:55 2017 +0200
>    drm/omapdrm: Move commit_modeset_enables() before commit_planes()
>    Move drm_atomic_helper_commit_modeset_enables() call to before
>    drm_atomic_helper_commit_planes() call and have a
>    omap_atomic_wait_for_completion() call after both.
>    With the current dss dispc implementation we have to enable the new
>    modeset before we can commit planes. The dispc ovl configuration
>    relies on the video mode configuration been written into the HW when
>    the ovl configuration is calculated.
>    This approach is not ideal because after a mode change the plane
>    update is executed only after the first vblank interrupt. The dispc
>    implementation should be fixed so that it is able use uncommitted drm
>    state information.  information.

***should*** probably means it does not :(

I wonder why Tomi did approve that. I think we should discuss with him
or ask to revert?

Maybe this bug is hidden with my setup of loaded kernel modules and other
letux-base patches which modify initialization sequence? Or it depends
on other details.


>    Signed-off-by: Jyri Sarha <jsarha at ti.com>
>    Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> git bisect log output:
> git bisect start
> # bad: [39da7c509acff13fc8cb12ec1bb20337c988ed36] Linux 4.11-rc6
> git bisect bad 39da7c509acff13fc8cb12ec1bb20337c988ed36
> # good: [c470abd4fde40ea6a0846a2beab642a578c0b8cd] Linux 4.10
> git bisect good c470abd4fde40ea6a0846a2beab642a578c0b8cd
> # good: [d5dee39b27201f9f5460eca55efcc91a663b738c] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
> git bisect good d5dee39b27201f9f5460eca55efcc91a663b738c
> # bad: [5d8a00eee2ed2e548a5d21b0edf495f3f7bf8bb4] Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
> git bisect bad 5d8a00eee2ed2e548a5d21b0edf495f3f7bf8bb4
> # good: [d5500a074741b78b7f778b4ab3415d5ecdcda0a7] Merge tag 'usercopy-v4.11-rc1.fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
> git bisect good d5500a074741b78b7f778b4ab3415d5ecdcda0a7
> # good: [29a73d906bd386839015602c4bd35ef2e3531abc] Merge branch 'drm-next-4.11' of git://people.freedesktop.org/~agd5f/linux into drm-next
> git bisect good 29a73d906bd386839015602c4bd35ef2e3531abc
> # bad: [699fa216808fff47efc9743f92f1b8a9f9bf5321] mm: fix handling PTE-mapped THPs in page_idle_clear_pte_refs()
> git bisect bad 699fa216808fff47efc9743f92f1b8a9f9bf5321
> # bad: [9b071c7935f053bf05ab4d0b2f4a8ae4069b4b89] drm/nouveau/pmu/gk20a: use falcon library functions
> git bisect bad 9b071c7935f053bf05ab4d0b2f4a8ae4069b4b89
> # good: [26d7f34cae7aad9600cd40ce07ec3fbe8606a567] Merge branch 'msm-next' of git://people.freedesktop.org/~robclark/linux into drm-next
> git bisect good 26d7f34cae7aad9600cd40ce07ec3fbe8606a567
> # good: [13f62f54d174d3417c3caaafedf5e22a0a03e442] Merge branch 'drm-next-4.11' of git://people.freedesktop.org/~agd5f/linux into drm-next
> git bisect good 13f62f54d174d3417c3caaafedf5e22a0a03e442
> # good: [be3c9f5eed3be89d17b5dcffc38412932214fbae] Merge branch 'drm-rockchip-next-2017-02-16' of https://github.com/markyzq/kernel-drm-rockchip into drm-next
> git bisect good be3c9f5eed3be89d17b5dcffc38412932214fbae
> # good: [dec13c8ba2f5be8839ba5505b57b22ab0d2a287e] Merge branch 'drm-next-4.11' of git://people.freedesktop.org/~agd5f/linux into drm-next
> git bisect good dec13c8ba2f5be8839ba5505b57b22ab0d2a287e
> # bad: [c1fcb14879e87c837c360c2ec9f32d19f62faf89] drm/nouveau/core: constify nv*_printk macros
> git bisect bad c1fcb14879e87c837c360c2ec9f32d19f62faf89
> # bad: [1b30ab0c40a99da347c1ab83c30b485e03fe9f64] drm/omapdrm: dispc: Refuse x-decimation above 4 for all but 8-bit formats
> git bisect bad 1b30ab0c40a99da347c1ab83c30b485e03fe9f64
> # bad: [897145d0c7010b4e07fa9bc674b1dfb9a2c6fff9] drm/omapdrm: Move commit_modeset_enables() before commit_planes()
> git bisect bad 897145d0c7010b4e07fa9bc674b1dfb9a2c6fff9
> # good: [e025d3860bd9f718d4d8ce251e6a823dd8293b51] Revert "drm: omapdrm: Let the DRM core skip plane commit on inactive CRTCs"
> git bisect good e025d3860bd9f718d4d8ce251e6a823dd8293b51
> # first bad commit: [897145d0c7010b4e07fa9bc674b1dfb9a2c6fff9] drm/omapdrm: Move commit_modeset_enables() before commit_planes()
> kernel commandline used:
> root at letux:~# cat /proc/cmdline
> console=tty0 mtdoops.mtddev=omap2.nand ubi.mtd=4 root=/dev/mmcblk0p3 rw rootfstype=ext4,ext3 rootwait vram=12M omapfb.vram=0:8M,1:4M omapfb.rotate_type=0 omapdss.def_disp=lcd rootwait twl4030_charger.allow_usb=1 musb_hdrc.preserve_vbus=1 log_buf_len=8M
> kernel config used is attached. I have compiled statically most of the
> twl4030 / usb stuff because we have patches in our feature branches to
> make that work as modules.

Yes, indeed. I should try to upstream such things...


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