[PATCH 6/8] drm/vram-helper: don't use ttm bo->offset v4

[Christian König]

Hi Thomas,

Am 17.09.20 um 12:51 schrieb Thomas Zimmermann:
> Hi
>
> Am 24.06.20 um 20:26 schrieb Nirmoy Das:
>> Calculate GEM VRAM bo's offset within vram-helper without depending on
>> bo->offset.
>>
>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>> ---
>>   drivers/gpu/drm/drm_gem_vram_helper.c | 11 ++++++++++-
>>   1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
>> index 0023ce1d2cf7..ad096600d89f 100644
>> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
>> @@ -281,6 +281,15 @@ u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo)
>>   }
>>   EXPORT_SYMBOL(drm_gem_vram_mmap_offset);
>>   
>> +static u64 drm_gem_vram_pg_offset(struct drm_gem_vram_object *gbo)
>> +{
>> +	/* Keep TTM behavior for now, remove when drivers are audited */
>> +	if (WARN_ON_ONCE(!gbo->bo.mem.mm_node))
> At this line I got

Sounds like ast forgot to pin the cursor to VRAM.

If you look at ast_cursor_page_flip(), you see:
>         off = drm_gem_vram_offset(gbo);
>         if (drm_WARN_ON_ONCE(dev, off < 0))
>                 return; /* Bug: we didn't pin the cursor HW BO to VRAM. */

The drm_WARN_ON_ONCE() just never triggered before because it checks for 
the wrong condition (off < 0).

Regards,
Christian.

>
> [  146.133821] ------------[ cut here ]------------
> [  146.133872] WARNING: CPU: 6 PID: 7 at
> drivers/gpu/drm/drm_gem_vram_helper.c:284 drm_gem_vram_offset+0x59/0x60
> [drm_vram_helper]
> [  146.133880] Modules linked in: fuse(E) af_packet(E) ebtable_filter(E)
> ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E)
> ip_tables(E) x_tables(E) bpfilter(E) rfkill(E) dmi_sysfs(E) msr(E)
> intel_powerclamp(E) coretemp(E) kv)
> [  146.134051]  scsi_dh_emc(E) scsi_dh_alua(E)
> [  146.134074] CPU: 6 PID: 7 Comm: kworker/u48:0 Tainted: G            E
>      5.9.0-rc4-1-default+ #492
> [  146.134083] Hardware name: Sun Microsystems SUN FIRE X2270 M2/SUN
> FIRE X2270 M2, BIOS 2.05    07/01/2010
> [  146.134099] Workqueue: events_unbound commit_work
> [  146.134116] RIP: 0010:drm_gem_vram_offset+0x59/0x60 [drm_vram_helper]
> [  146.134128] Code: 02 00 00 00 74 24 48 8d bb 80 02 00 00 e8 ef 27 17
> d7 48 8b 83 80 02 00 00 5b 48 c1 e0 0c c3 0f 0b 48 c7 c0 ed ff ff ff 5b
> c3 <0f> 0b 31 c0 5b c3 90 66 66 66 66 90 41 56 41 55 49 89 d5 41 54 49
> [  146.134137] RSP: 0018:ffffc90000107c38 EFLAGS: 00010246
> [  146.134149] RAX: 0000000000000000 RBX: ffff888111155000 RCX:
> ffffffffc032323b
> [  146.134158] RDX: dffffc0000000000 RSI: ffff88810e236300 RDI:
> ffff888111155278
> [  146.134168] RBP: ffff888109090000 R08: ffffffffc0323225 R09:
> 0000000000000002
> [  146.134177] R10: ffffed1020675020 R11: 0000000000000001 R12:
> ffff888109091050
> [  146.134187] R13: ffff88810e236300 R14: ffff888109090000 R15:
> 0000000000000000
> [  146.134197] FS:  0000000000000000(0000) GS:ffff888116000000(0000)
> knlGS:0000000000000000
> [  146.134206] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  146.134215] CR2: 00007f60547d9100 CR3: 0000000029216002 CR4:
> 00000000000206e0
> [  146.134223] Call Trace:
> [  146.134245]  ast_cursor_page_flip+0x3e/0x150 [ast]
> [  146.134272]  ast_cursor_plane_helper_atomic_update+0x8a/0xc0 [ast]
> [  146.134300]  drm_atomic_helper_commit_planes+0x197/0x4c0
> [  146.134341]  drm_atomic_helper_commit_tail_rpm+0x51/0x90
> [  146.134357]  commit_tail+0x103/0x1c0
> [  146.134390]  process_one_work+0x56a/0xa60
> [  146.134431]  ? __lock_acquired+0x1ca/0x3d0
> [  146.134447]  ? pwq_dec_nr_in_flight+0x110/0x110
> [  146.134460]  ? __lock_contended+0x4a0/0x4a0
> [  146.134491]  ? worker_thread+0x150/0x620
> [  146.134521]  worker_thread+0x8b/0x620
> [  146.134539]  ? _raw_spin_unlock_irqrestore+0x41/0x50
> [  146.134583]  ? process_one_work+0xa60/0xa60
> [  146.134597]  kthread+0x1e4/0x210
> [  146.134612]  ? kthread_create_worker_on_cpu+0xb0/0xb0
> [  146.134637]  ret_from_fork+0x22/0x30
> [  146.134698] irq event stamp: 74111
> [  146.134711] hardirqs last  enabled at (74117): [<ffffffff971c68f9>]
> console_unlock+0x539/0x670
> [  146.134723] hardirqs last disabled at (74122): [<ffffffff971c68ef>]
> console_unlock+0x52f/0x670
> [  146.134737] softirqs last  enabled at (73354): [<ffffffff975469d5>]
> wb_workfn+0x3f5/0x430
> [  146.134749] softirqs last disabled at (73350): [<ffffffff973f81d0>]
> wb_wakeup_delayed+0x40/0xa0
> [  146.134758] ---[ end trace 74dd5fac6a3a2c0c ]---
>
>
> Happens with ast when doing
>
>    weston-launch
>
>
>
>> +		return 0;
>> +
>> +	return gbo->bo.mem.start;
>> +}
>> +
>>   /**
>>    * drm_gem_vram_offset() - \
>>   	Returns a GEM VRAM object's offset in video memory
>> @@ -297,7 +306,7 @@ s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo)
>>   {
>>   	if (WARN_ON_ONCE(!gbo->pin_count))
>>   		return (s64)-ENODEV;
>> -	return gbo->bo.offset;
>> +	return drm_gem_vram_pg_offset(gbo) << PAGE_SHIFT;
>>   }
>>   EXPORT_SYMBOL(drm_gem_vram_offset);
>>   
>>