Message-ID: <9dabba6c-95fb-ac42-9be8-b52e7732a231@suse.de>
Date:   Fri, 20 Nov 2020 09:05:02 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     David Laight <David.Laight@...LAB.COM>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Daniel Vetter <daniel.vetter@...ll.ch>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        "Huang, Ray" <ray.huang@....com>, Dave Airlie <airlied@...hat.com>,
        Christian König <christian.koenig@....com>
Subject: Re: Linux 5.10-rc4

Hi David

Am 18.11.20 um 23:01 schrieb David Laight:
> From: Thomas Zimmermann
>> Sent: 18 November 2020 19:37
>>
>> Hi
>>
>> Am 18.11.20 um 19:10 schrieb Linus Torvalds:
>>> On Wed, Nov 18, 2020 at 4:12 AM David Laight <David.Laight@...lab.com> wrote:
>>>>
>>>> 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 don't quite understand what 'git bisect' did.
> I was bisecting between v5.9 and v5.10-rc1 but it suddenly started
> generating v5.9.0-rc5+ kernels.
> 
> The identified commit was 13a8f46d803 drm/ttm: move ghost object created.
> (retyped - hope it is right).
> But the diff to that last 'good' commit is massive.
> 
> So I don't know if that is anywhere near right.

Did you try Daniel's suggestion of testing with the direct parent commit?

Best regards
Thomas

> 
> 	David
> 
>>>
>>> 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_helper.c:284
>> drm_gem_vram_offset+0x35/0x40 [drm_vram_helper]
>>
>> That line is at [1], which comes from
>>
>>    46642a7d4d80 ("drm/vram-helper: don't use ttm bo->offset v4")
>>
>> But the patch was merged in 5.9-rc1, so it's probably something else.
>>
>> We've had a lot of TTM-related changes recently, so my best guess is
>> that it's something in TTM with BO initialization.
>>
>>   From some grepping, it looks like we have to call ttm_bo_mem_space() to
>> fill mm_node (i.e., the pointer that causes the warning). But I cannot
>> find where vram helpers do this. Maybe that's a good starting point.
>>
>> I'm adding the TTM devs to cc.
>>
>> Best regards
>> Thomas
>>
>> [1]
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/drm_gem_vram_h
>> elper.c?h=v5.10-rc4#n284
>>
>>
>>>> [   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_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs
>> blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcpy 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_clmulni_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 08/27/2015
>>>> [   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 18 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: ffffffffc032d600
>>>> [   20.938479] RDX: ffff8b468f47a000 RSI: ffff8b46861e2000 RDI: ffff8b468f9acc00
>>>> [   20.945622] RBP: ffff9f59811d3a68 R08: 0000000000000040 R09: ffff8b46864ce288
>>>> [   20.952769] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8b468f47a000
>>>> [   20.959915] R13: 0000000000000000 R14: 0000000000000000 R15: ffff8b468ad2bf00
>>>> [   20.967057] FS:  00007f5b37ac5cc0(0000) GS:ffff8b49efc00000(0000) knlGS:0000000000000000
>>>> [   20.975149] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>> [   20.980904] CR2: 00007f5b3d093f00 CR3: 0000000103438000 CR4: 00000000001006f0
>>>> [   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_helper]
>>>> [   21.008243]  drm_atomic_helper_commit_tail_rpm+0x3a/0x70 [drm_kms_helper]
>>>> [   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 48 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: 0000000000000010
>>>> [   21.121730] RAX: ffffffffffffffda RBX: 00007ffef19665c0 RCX: 00007f5b3cf1350b
>>>> [   21.128870] RDX: 00007ffef19665c0 RSI: 00000000c02464bb RDI: 0000000000000009
>>>> [   21.136013] RBP: 00000000c02464bb R08: 0000000000000040 R09: 0000000000000004
>>>> [   21.143157] R10: 0000000000000002 R11: 0000000000000246 R12: 0000561ec9d10060
>>>> [   21.150295] R13: 0000000000000009 R14: 0000561eca2cc9a0 R15: 0000000000000040
>>
>> --
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>> (HRB 36809, AG Nürnberg)
>> Geschäftsführer: Felix Imendörffer
> 
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
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> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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