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Message-ID: <DM6PR12MB4137B67100E8C5F038AE4AAFFC040@DM6PR12MB4137.namprd12.prod.outlook.com>
Date:   Thu, 30 Jan 2020 10:40:33 +0000
From:   "Lin, Wayne" <Wayne.Lin@....com>
To:     Lyude Paul <lyude@...hat.com>,
        "Lipski, Mikita" <Mikita.Lipski@....com>,
        "Wentland, Harry" <Harry.Wentland@....com>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>
CC:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "Wentland, Harry" <Harry.Wentland@....com>,
        "Li, Sun peng (Leo)" <Sunpeng.Li@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Zhou, David(ChunMing)" <David1.Zhou@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "Lakha, Bhawanpreet" <Bhawanpreet.Lakha@....com>,
        "Lipski, Mikita" <Mikita.Lipski@....com>,
        Sam Ravnborg <sam@...nborg.org>,
        David Francis <David.Francis@....com>,
        "Tsai, Martin" <Martin.Tsai@....com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        "Lee, Alvin" <Alvin.Lee2@....com>, Jean Delvare <jdelvare@...e.de>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] drm/amd/dm/mst: Ignore payload update failures on disable

[AMD Public Use]

Hi Lyude,

Thanks for the patch!
I'm wondering if this error still occurs with this patch applied
https://patchwork.kernel.org/patch/11274363/
I tried to clean up all mgr->proposed_vcpis[] in this patch so
drm_dp_update_payload_part1() will skip all invalid ports.

However, I'm also thinking to improve this patch.
Maybe it is better to do cleaning proposed_vcpis[] in 
dm_helpers_dp_mst_write_payload_allocation_table() due to
it is the actual place that DC try to update the status for a specific 
VC stream. If it's reasonable then I'll do that in the future :)

> -----Original Message-----
> From: Lyude Paul <lyude@...hat.com>
> Sent: Saturday, January 25, 2020 2:57 AM
> To: Lipski, Mikita <Mikita.Lipski@....com>; Wentland, Harry
> <Harry.Wentland@....com>; amd-gfx@...ts.freedesktop.org
> Cc: stable@...r.kernel.org; Wentland, Harry <Harry.Wentland@....com>; Li,
> Sun peng (Leo) <Sunpeng.Li@....com>; Deucher, Alexander
> <Alexander.Deucher@....com>; Koenig, Christian
> <Christian.Koenig@....com>; Zhou, David(ChunMing)
> <David1.Zhou@....com>; David Airlie <airlied@...ux.ie>; Daniel Vetter
> <daniel@...ll.ch>; Lakha, Bhawanpreet <Bhawanpreet.Lakha@....com>;
> Lipski, Mikita <Mikita.Lipski@....com>; Sam Ravnborg <sam@...nborg.org>;
> David Francis <David.Francis@....com>; Tsai, Martin
> <Martin.Tsai@....com>; Chris Wilson <chris@...is-wilson.co.uk>; Lee, Alvin
> <Alvin.Lee2@....com>; Jean Delvare <jdelvare@...e.de>;
> dri-devel@...ts.freedesktop.org; linux-kernel@...r.kernel.org; Lin, Wayne
> <Wayne.Lin@....com>
> Subject: Re: [PATCH] drm/amd/dm/mst: Ignore payload update failures on
> disable
> 
> 
> 
> On Fri, 2020-01-24 at 11:39 -0500, Mikita Lipski wrote:
> >
> > On 1/24/20 9:55 AM, Harry Wentland wrote:
> > > On 2020-01-23 7:06 p.m., Lyude Paul wrote:
> > > > Disabling a display on MST can potentially happen after the entire
> > > > MST topology has been removed, which means that we can't
> > > > communicate with the topology at all in this scenario. Likewise,
> > > > this also means that we can't properly update payloads on the
> > > > topology and as such, it's a good idea to ignore payload update failures
> when disabling displays.
> > > > Currently, amdgpu makes the mistake of halting the payload update
> > > > process when any payload update failures occur, resulting in
> > > > leaving DC's local copies of the payload tables out of date.
> > > >
> > > > This ends up causing problems with hotplugging MST topologies, and
> > > > causes modesets on the second hotplug to fail like so:
> > > >
> > > > [drm] Failed to updateMST allocation table forpipe idx:1
> > > > ------------[ cut here ]------------
> > > > WARNING: CPU: 5 PID: 1511 at
> > > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link.c:2677
> > > > update_mst_stream_alloc_table+0x11e/0x130 [amdgpu] Modules linked
> > > > in: cdc_ether usbnet fuse xt_conntrack nf_conntrack
> > > > nf_defrag_ipv6 libcrc32c nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4
> > > > nft_counter nft_compat nf_tables nfnetlink tun bridge stp llc
> > > > sunrpc vfat fat wmi_bmof uvcvideo snd_hda_codec_realtek
> > > > snd_hda_codec_generic snd_hda_codec_hdmi videobuf2_vmalloc
> > > > snd_hda_intel videobuf2_memops
> > > > videobuf2_v4l2 snd_intel_dspcfg videobuf2_common crct10dif_pclmul
> > > > snd_hda_codec videodev crc32_pclmul snd_hwdep snd_hda_core
> > > > ghash_clmulni_intel snd_seq mc joydev pcspkr snd_seq_device
> > > > snd_pcm sp5100_tco k10temp i2c_piix4 snd_timer thinkpad_acpi
> > > > ledtrig_audio snd wmi soundcore video i2c_scmi acpi_cpufreq
> > > > ip_tables amdgpu(O) rtsx_pci_sdmmc amd_iommu_v2 gpu_sched
> mmc_core
> > > > i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt
> > > > fb_sys_fops cec drm crc32c_intel serio_raw hid_multitouch r8152
> > > > mii nvme r8169 nvme_core rtsx_pci pinctrl_amd
> > > > CPU: 5 PID: 1511 Comm: gnome-shell Tainted: G           O
> 5.5.0-
> > > > rc7Lyude-Test+ #4
> > > > Hardware name: LENOVO FA495SIT26/FA495SIT26, BIOS
> R12ET22W(0.22 )
> > > > 01/31/2019
> > > > RIP: 0010:update_mst_stream_alloc_table+0x11e/0x130 [amdgpu]
> > > > Code: 28 00 00 00 75 2b 48 8d 65 e0 5b 41 5c 41 5d 41 5e 5d c3 0f
> > > > b6 06
> > > > 49 89 1c 24 41 88 44 24 08 0f b6 46 01 41 88 44 24 09 eb 93 <0f>
> > > > 0b e9 2f ff ff ff e8 a6 82 a3 c2 66 0f 1f 44 00 00 0f 1f 44 00
> > > > RSP: 0018:ffffac428127f5b0 EFLAGS: 00010202
> > > > RAX: 0000000000000002 RBX: ffff8d1e166eee80 RCX:
> 0000000000000000
> > > > RDX: ffffac428127f668 RSI: ffff8d1e166eee80 RDI: ffffac428127f610
> > > > RBP: ffffac428127f640 R08: ffffffffc03d94a8 R09: 0000000000000000
> > > > R10: ffff8d1e24b02000 R11: ffffac428127f5b0 R12: ffff8d1e1b83d000
> > > > R13: ffff8d1e1bea0b08 R14: 0000000000000002 R15:
> 0000000000000002
> > > > FS:  00007fab23ffcd80(0000) GS:ffff8d1e28b40000(0000)
> > > > knlGS:0000000000000000
> > > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > > CR2: 00007f151f1711e8 CR3: 00000005997c0000 CR4:
> 00000000003406e0
> > > > Call Trace:
> > > >   ? mutex_lock+0xe/0x30
> > > >   dc_link_allocate_mst_payload+0x9a/0x210 [amdgpu]
> > > >   ? dm_read_reg_func+0x39/0xb0 [amdgpu]
> > > >   ? core_link_enable_stream+0x656/0x730 [amdgpu]
> > > >   core_link_enable_stream+0x656/0x730 [amdgpu]
> > > >   dce110_apply_ctx_to_hw+0x58e/0x5d0 [amdgpu]
> > > >   ? dcn10_verify_allow_pstate_change_high+0x1d/0x280 [amdgpu]
> > > >   ? dcn10_wait_for_mpcc_disconnect+0x3c/0x130 [amdgpu]
> > > >   dc_commit_state+0x292/0x770 [amdgpu]
> > > >   ? add_timer+0x101/0x1f0
> > > >   ? ttm_bo_put+0x1a1/0x2f0 [ttm]
> > > >   amdgpu_dm_atomic_commit_tail+0xb59/0x1ff0 [amdgpu]
> > > >   ? amdgpu_move_blit.constprop.0+0xb8/0x1f0 [amdgpu]
> > > >   ? amdgpu_bo_move+0x16d/0x2b0 [amdgpu]
> > > >   ? ttm_bo_handle_move_mem+0x118/0x570 [ttm]
> > > >   ? ttm_bo_validate+0x134/0x150 [ttm]
> > > >   ? dm_plane_helper_prepare_fb+0x1b9/0x2a0 [amdgpu]
> > > >   ? _cond_resched+0x15/0x30
> > > >   ? wait_for_completion_timeout+0x38/0x160
> > > >   ? _cond_resched+0x15/0x30
> > > >   ? wait_for_completion_interruptible+0x33/0x190
> > > >   commit_tail+0x94/0x130 [drm_kms_helper]
> > > >   drm_atomic_helper_commit+0x113/0x140 [drm_kms_helper]
> > > >   drm_atomic_helper_set_config+0x70/0xb0 [drm_kms_helper]
> > > >   drm_mode_setcrtc+0x194/0x6a0 [drm]
> > > >   ? _cond_resched+0x15/0x30
> > > >   ? mutex_lock+0xe/0x30
> > > >   ? drm_mode_getcrtc+0x180/0x180 [drm]
> > > >   drm_ioctl_kernel+0xaa/0xf0 [drm]
> > > >   drm_ioctl+0x208/0x390 [drm]
> > > >   ? drm_mode_getcrtc+0x180/0x180 [drm]
> > > >   amdgpu_drm_ioctl+0x49/0x80 [amdgpu]
> > > >   do_vfs_ioctl+0x458/0x6d0
> > > >   ksys_ioctl+0x5e/0x90
> > > >   __x64_sys_ioctl+0x16/0x20
> > > >   do_syscall_64+0x55/0x1b0
> > > >   entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > > > RIP: 0033:0x7fab2121f87b
> > > > Code: 0f 1e fa 48 8b 05 0d 96 2c 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 dd 95 2c 00 f7 d8 64 89 01 48
> > > > RSP: 002b:00007ffd045f9068 EFLAGS: 00000246 ORIG_RAX:
> > > > 0000000000000010
> > > > RAX: ffffffffffffffda RBX: 00007ffd045f90a0 RCX: 00007fab2121f87b
> > > > RDX: 00007ffd045f90a0 RSI: 00000000c06864a2 RDI: 000000000000000b
> > > > RBP: 00007ffd045f90a0 R08: 0000000000000000 R09:
> 000055dbd2985d10
> > > > R10: 000055dbd2196280 R11: 0000000000000246 R12:
> 00000000c06864a2
> > > > R13: 000000000000000b R14: 0000000000000000 R15:
> 000055dbd2196280
> > > > ---[ end trace 6ea888c24d2059cd ]---
> > > >
> > > > Note as well, I have only been able to reproduce this on setups
> > > > with 2 MST displays.
> > > >
> > > > Signed-off-by: Lyude Paul <lyude@...hat.com>
> > > > Cc: stable@...r.kernel.org
> > >
> > > LGTM but would like Mikita or Wayne to have a look as well.
> > > Acked-by: Harry Wentland <harry.wentland@....com>
> >
> > I think its a good change and it definetely helps to deal with
> > discreptency between drm and dc payload allocation tables.
> > But I think we might not even need extra enable checks.
> 
> I think you're right here, I'll remove those in the next respin
> 
> >
> > > Harry
> > >
> > > > ---
> > > >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 7
> ++++---
> > > >   1 file changed, 4 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git
> > > > a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > > > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > > > index 069b7a6f5597..252fa60c6775 100644
> > > > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > > > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> > > > @@ -216,6 +216,7 @@ bool
> > > > dm_helpers_dp_mst_write_payload_allocation_table(
> > > >   		drm_dp_mst_reset_vcpi_slots(mst_mgr, mst_port);
> > > >   	}
> > > >
> > > > +	/* If disabling, it's OK for this to fail */
> > > >   	ret = drm_dp_update_payload_part1(mst_mgr);
> > > >
> > > >   	/* mst_mgr->->payloads are VC payload notify MST branch using
> > > > DPCD or @@ -225,7 +226,7 @@ bool
> > > > dm_helpers_dp_mst_write_payload_allocation_table(
> > > >
> > > >   	get_payload_table(aconnector, proposed_table);
> > > >
> > > > -	if (ret)
> > > > +	if (ret && !enable)
> > > >   		return false;
> >
> > Wouldn't it be better to check ret value, and instead of returning
> > false just throw DRM_ERROR message, since drm_dp_update_payload_part1
> > only returns error if a port is not validated?
> 
> You're right on avoiding returning here, that's probably a better idea since we
> want all steps to be run even if they don't succeed. I think we can skip the
> error message though, it's expected that modesets which disable displays will
> happen on ports that no longer can be validated.
> 
> >
> > Thank you,
> > Mikita
> >
> > > >
> > > >   	return true;
> > > > @@ -299,9 +300,9 @@ bool
> dm_helpers_dp_mst_send_payload_allocation(
> > > >   	if (!mst_mgr->mst_state)
> > > >   		return false;
> > > >
> > > > +	/* If disabling, it's OK for this to fail */
> > > >   	ret = drm_dp_update_payload_part2(mst_mgr);
> > > > -
> > > > -	if (ret)
> > > > +	if (enable && ret)
> > > >   		return false;
> > > >
> > > >   	if (!enable)
> --
> Cheers,
> 	Lyude Paul
--
Best regards,
Wayne Lin

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