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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 18 Nov 2020 10:10:37 -0800
Message-ID: <CAHk-=wgQY7k_3NVCbaSmiJyLiAV_1TgwLk-d4QRMHMWqM5Oo_w@mail.gmail.com>
Subject: Re: Linux 5.10-rc4
To:     David Laight <David.Laight@aculab.com>,
        Thomas Zimmermann <tzimmermann@suse.de>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Dave Airlie <airlied@redhat.com>,
        dri-devel <dri-devel@lists.freedesktop.org>
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On Wed, Nov 18, 2020 at 4:12 AM David Laight <David.Laight@aculab.com> wrot=
e:
>
> I've got the 'splat' below during boot.
> This is an 8-core C2758 Atom cpu using the on-board/cpu graphics.
> User space is Ubuntu 20.04.
>
> Additionally the X display has all the colours and alignment slightly
> messed up.
> 5.9.0 was ok.
> I'm just guessing the two issues are related.

Sounds likely.  But it would be lovely if you could bisect when
exactly the problem(s) started to both verify that, and just to
pinpoint the exact change..

I'm adding Thomas Zimmermann to the cc, because he did that "drm/ast:
Program display mode in CRTC's atomic_enable" which looks relevant in
that it's right in that call-chain.

Did some initialization perhaps get overlooked?

And Dave and Daniel and the drm list cc'd as well..

Full splat left quoted below for new people and list.

            Linus

> [   20.809891] WARNING: CPU: 0 PID: 973 at drivers/gpu/drm/drm_gem_vram_h=
elper.c:284 drm_gem_vram_offset+0x35/0x40 [drm_vram_helper]
> [   20.821543] Modules linked in: nls_iso8859_1 dm_multipath scsi_dh_rdac=
 scsi_dh_emc scsi_dh_alua ipmi_ssif intel_powerclamp coretemp kvm_intel kvm=
 joydev input_leds ipmi_si intel_cstate ipmi_devintf ipmi_msghandler mac_hi=
d sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs=
 blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcp=
y async_pq async_xor async_tx libcrc32c xor raid6_pq raid1 raid0 multipath =
linear ast drm_vram_helper drm_kms_helper syscopyarea sysfillrect sysimgblt=
 fb_sys_fops cec drm_ttm_helper ttm crct10dif_pclmul crc32_pclmul ghash_clm=
ulni_intel gpio_ich drm aesni_intel hid_generic glue_helper crypto_simd igb=
 usbhid cryptd ahci i2c_i801 hid libahci i2c_smbus lpc_ich dca i2c_ismt i2c=
_algo_bit
> [   20.887477] CPU: 0 PID: 973 Comm: gnome-shell Not tainted 5.10.0-rc4+ =
#78
> [   20.894274] Hardware name: Supermicro A1SAi/A1SRi, BIOS 1.1a 08/27/201=
5
> [   20.900896] RIP: 0010:drm_gem_vram_offset+0x35/0x40 [drm_vram_helper]
> [   20.907342] Code: 00 48 89 e5 85 c0 74 17 48 83 bf 78 01 00 00 00 74 1=
8 48 8b 87 80 01 00 00 5d 48 c1 e0 0c c3 0f 0b 48 c7 c0 ed ff ff ff 5d c3 <=
0f> 0b 31 c0 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 8b 87 18 06
> [   20.926100] RSP: 0018:ffff9f59811d3a68 EFLAGS: 00010246
> [   20.931339] RAX: 0000000000000002 RBX: ffff8b46861e20c0 RCX: ffffffffc=
032d600
> [   20.938479] RDX: ffff8b468f47a000 RSI: ffff8b46861e2000 RDI: ffff8b468=
f9acc00
> [   20.945622] RBP: ffff9f59811d3a68 R08: 0000000000000040 R09: ffff8b468=
64ce288
> [   20.952769] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8b468=
f47a000
> [   20.959915] R13: 0000000000000000 R14: 0000000000000000 R15: ffff8b468=
ad2bf00
> [   20.967057] FS:  00007f5b37ac5cc0(0000) GS:ffff8b49efc00000(0000) knlG=
S:0000000000000000
> [   20.975149] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   20.980904] CR2: 00007f5b3d093f00 CR3: 0000000103438000 CR4: 000000000=
01006f0
> [   20.988047] Call Trace:
> [   20.990506]  ast_cursor_page_flip+0x22/0x100 [ast]
> [   20.995313]  ast_cursor_plane_helper_atomic_update+0x46/0x70 [ast]
> [   21.001524]  drm_atomic_helper_commit_planes+0xbd/0x220 [drm_kms_helpe=
r]
> [   21.008243]  drm_atomic_helper_commit_tail_rpm+0x3a/0x70 [drm_kms_help=
er]
> [   21.015062]  commit_tail+0x99/0x130 [drm_kms_helper]
> [   21.020050]  drm_atomic_helper_commit+0x123/0x150 [drm_kms_helper]
> [   21.026269]  drm_atomic_commit+0x4a/0x50 [drm]
> [   21.030737]  drm_atomic_helper_update_plane+0xe7/0x140 [drm_kms_helper=
]
> [   21.037384]  __setplane_atomic+0xcc/0x110 [drm]
> [   21.041953]  drm_mode_cursor_universal+0x13e/0x260 [drm]
> [   21.047299]  drm_mode_cursor_common+0xef/0x220 [drm]
> [   21.052287]  ? alloc_set_pte+0x10d/0x6d0
> [   21.056244]  ? drm_mode_cursor_ioctl+0x60/0x60 [drm]
> [   21.061242]  drm_mode_cursor2_ioctl+0xe/0x10 [drm]
> [   21.066067]  drm_ioctl_kernel+0xae/0xf0 [drm]
> [   21.070455]  drm_ioctl+0x241/0x3f0 [drm]
> [   21.074415]  ? drm_mode_cursor_ioctl+0x60/0x60 [drm]
> [   21.079401]  __x64_sys_ioctl+0x91/0xc0
> [   21.083167]  do_syscall_64+0x38/0x90
> [   21.086755]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [   21.091813] RIP: 0033:0x7f5b3cf1350b
> [   21.095403] Code: 0f 1e fa 48 8b 05 85 39 0d 00 64 c7 00 26 00 00 00 4=
8 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <=
48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 55 39 0d 00 f7 d8 64 89 01 48
> [   21.114154] RSP: 002b:00007ffef1966588 EFLAGS: 00000246 ORIG_RAX: 0000=
000000000010
> [   21.121730] RAX: ffffffffffffffda RBX: 00007ffef19665c0 RCX: 00007f5b3=
cf1350b
> [   21.128870] RDX: 00007ffef19665c0 RSI: 00000000c02464bb RDI: 000000000=
0000009
> [   21.136013] RBP: 00000000c02464bb R08: 0000000000000040 R09: 000000000=
0000004
> [   21.143157] R10: 0000000000000002 R11: 0000000000000246 R12: 0000561ec=
9d10060
> [   21.150295] R13: 0000000000000009 R14: 0000561eca2cc9a0 R15: 000000000=
0000040