<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/gpu/drm/amd/display, branch v4.20-rc3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>drm/amd/amdgpu/dm: Fix dm_dp_create_fake_mst_encoder()</title>
<updated>2018-11-07T23:21:05+00:00</updated>
<author>
<name>Lyude Paul</name>
<email>lyude@redhat.com</email>
</author>
<published>2018-11-02T01:51:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=63237f8748bdf46dccf79ef8f98f05e9fe799162'/>
<id>63237f8748bdf46dccf79ef8f98f05e9fe799162</id>
<content type='text'>
[why]
Removing connector reusage from DM to match the rest of the tree ended
up revealing an issue that was surprisingly subtle. The original amdgpu
code for DC that was submitted appears to have left a chunk in
dm_dp_create_fake_mst_encoder() that tries to find a "master encoder",
the likes of which isn't actually used or stored anywhere. It does so at
the wrong time as well by trying to access parts of the drm_connector
from the encoder init before it's actually been initialized. This
results in a NULL pointer deref on MST hotplugs:

[  160.696613] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[  160.697234] PGD 0 P4D 0
[  160.697814] Oops: 0010 [#1] SMP PTI
[  160.698430] CPU: 2 PID: 64 Comm: kworker/2:1 Kdump: loaded Tainted: G           O      4.19.0Lyude-Test+ #2
[  160.699020] Hardware name: HP HP ZBook 15 G4/8275, BIOS P70 Ver. 01.22 05/17/2018
[  160.699672] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
[  160.700322] RIP: 0010:          (null)
[  160.700920] Code: Bad RIP value.
[  160.701541] RSP: 0018:ffffc9000029fc78 EFLAGS: 00010206
[  160.702183] RAX: 0000000000000000 RBX: ffff8804440ed468 RCX: ffff8804440e9158
[  160.702778] RDX: 0000000000000000 RSI: ffff8804556c5700 RDI: ffff8804440ed000
[  160.703408] RBP: ffff880458e21800 R08: 0000000000000002 R09: 000000005fca0a25
[  160.704002] R10: ffff88045a077a3d R11: ffff88045a077a3c R12: ffff8804440ed000
[  160.704614] R13: ffff880458e21800 R14: ffff8804440e9000 R15: ffff8804440e9000
[  160.705260] FS:  0000000000000000(0000) GS:ffff88045f280000(0000) knlGS:0000000000000000
[  160.705854] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  160.706478] CR2: ffffffffffffffd6 CR3: 000000000200a001 CR4: 00000000003606e0
[  160.707124] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  160.707724] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  160.708372] Call Trace:
[  160.708998]  ? dm_dp_add_mst_connector+0xed/0x1d0 [amdgpu]
[  160.709625]  ? drm_dp_add_port+0x2fa/0x470 [drm_kms_helper]
[  160.710284]  ? wake_up_q+0x54/0x70
[  160.710877]  ? __mutex_unlock_slowpath.isra.18+0xb3/0x110
[  160.711512]  ? drm_dp_dpcd_access+0xe7/0x110 [drm_kms_helper]
[  160.712161]  ? drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
[  160.712762]  ? drm_dp_check_and_send_link_address+0xa3/0xd0 [drm_kms_helper]
[  160.713408]  ? drm_dp_mst_link_probe_work+0x4b/0x80 [drm_kms_helper]
[  160.714013]  ? process_one_work+0x1a1/0x3a0
[  160.714667]  ? worker_thread+0x30/0x380
[  160.715326]  ? wq_update_unbound_numa+0x10/0x10
[  160.715939]  ? kthread+0x112/0x130
[  160.716591]  ? kthread_create_worker_on_cpu+0x70/0x70
[  160.717262]  ? ret_from_fork+0x35/0x40
[  160.717886] Modules linked in: amdgpu(O) vfat fat snd_hda_codec_generic joydev i915 chash gpu_sched ttm i2c_algo_bit drm_kms_helper snd_hda_codec_hdmi hp_wmi syscopyarea iTCO_wdt sysfillrect sparse_keymap sysimgblt fb_sys_fops snd_hda_intel usbhid wmi_bmof drm snd_hda_codec btusb snd_hda_core intel_rapl btrtl x86_pkg_temp_thermal btbcm btintel coretemp snd_pcm crc32_pclmul bluetooth psmouse snd_timer snd pcspkr i2c_i801 mei_me i2c_core soundcore mei tpm_tis wmi tpm_tis_core hp_accel ecdh_generic lis3lv02d tpm video rfkill acpi_pad input_polldev hp_wireless pcc_cpufreq crc32c_intel serio_raw tg3 xhci_pci xhci_hcd [last unloaded: amdgpu]
[  160.720141] CR2: 0000000000000000

Somehow the connector reusage DM was using for MST connectors managed to
paper over this issue entirely; hence why this was never caught until
now.

[how]
Since this code isn't used anywhere and seems useless anyway, we can
just drop it entirely. This appears to fix the issue on my HP ZBook with
an AMD WX4150.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[why]
Removing connector reusage from DM to match the rest of the tree ended
up revealing an issue that was surprisingly subtle. The original amdgpu
code for DC that was submitted appears to have left a chunk in
dm_dp_create_fake_mst_encoder() that tries to find a "master encoder",
the likes of which isn't actually used or stored anywhere. It does so at
the wrong time as well by trying to access parts of the drm_connector
from the encoder init before it's actually been initialized. This
results in a NULL pointer deref on MST hotplugs:

[  160.696613] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[  160.697234] PGD 0 P4D 0
[  160.697814] Oops: 0010 [#1] SMP PTI
[  160.698430] CPU: 2 PID: 64 Comm: kworker/2:1 Kdump: loaded Tainted: G           O      4.19.0Lyude-Test+ #2
[  160.699020] Hardware name: HP HP ZBook 15 G4/8275, BIOS P70 Ver. 01.22 05/17/2018
[  160.699672] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper]
[  160.700322] RIP: 0010:          (null)
[  160.700920] Code: Bad RIP value.
[  160.701541] RSP: 0018:ffffc9000029fc78 EFLAGS: 00010206
[  160.702183] RAX: 0000000000000000 RBX: ffff8804440ed468 RCX: ffff8804440e9158
[  160.702778] RDX: 0000000000000000 RSI: ffff8804556c5700 RDI: ffff8804440ed000
[  160.703408] RBP: ffff880458e21800 R08: 0000000000000002 R09: 000000005fca0a25
[  160.704002] R10: ffff88045a077a3d R11: ffff88045a077a3c R12: ffff8804440ed000
[  160.704614] R13: ffff880458e21800 R14: ffff8804440e9000 R15: ffff8804440e9000
[  160.705260] FS:  0000000000000000(0000) GS:ffff88045f280000(0000) knlGS:0000000000000000
[  160.705854] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  160.706478] CR2: ffffffffffffffd6 CR3: 000000000200a001 CR4: 00000000003606e0
[  160.707124] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  160.707724] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  160.708372] Call Trace:
[  160.708998]  ? dm_dp_add_mst_connector+0xed/0x1d0 [amdgpu]
[  160.709625]  ? drm_dp_add_port+0x2fa/0x470 [drm_kms_helper]
[  160.710284]  ? wake_up_q+0x54/0x70
[  160.710877]  ? __mutex_unlock_slowpath.isra.18+0xb3/0x110
[  160.711512]  ? drm_dp_dpcd_access+0xe7/0x110 [drm_kms_helper]
[  160.712161]  ? drm_dp_send_link_address+0x155/0x1e0 [drm_kms_helper]
[  160.712762]  ? drm_dp_check_and_send_link_address+0xa3/0xd0 [drm_kms_helper]
[  160.713408]  ? drm_dp_mst_link_probe_work+0x4b/0x80 [drm_kms_helper]
[  160.714013]  ? process_one_work+0x1a1/0x3a0
[  160.714667]  ? worker_thread+0x30/0x380
[  160.715326]  ? wq_update_unbound_numa+0x10/0x10
[  160.715939]  ? kthread+0x112/0x130
[  160.716591]  ? kthread_create_worker_on_cpu+0x70/0x70
[  160.717262]  ? ret_from_fork+0x35/0x40
[  160.717886] Modules linked in: amdgpu(O) vfat fat snd_hda_codec_generic joydev i915 chash gpu_sched ttm i2c_algo_bit drm_kms_helper snd_hda_codec_hdmi hp_wmi syscopyarea iTCO_wdt sysfillrect sparse_keymap sysimgblt fb_sys_fops snd_hda_intel usbhid wmi_bmof drm snd_hda_codec btusb snd_hda_core intel_rapl btrtl x86_pkg_temp_thermal btbcm btintel coretemp snd_pcm crc32_pclmul bluetooth psmouse snd_timer snd pcspkr i2c_i801 mei_me i2c_core soundcore mei tpm_tis wmi tpm_tis_core hp_accel ecdh_generic lis3lv02d tpm video rfkill acpi_pad input_polldev hp_wireless pcc_cpufreq crc32c_intel serio_raw tg3 xhci_pci xhci_hcd [last unloaded: amdgpu]
[  160.720141] CR2: 0000000000000000

Somehow the connector reusage DM was using for MST connectors managed to
paper over this issue entirely; hence why this was never caught until
now.

[how]
Since this code isn't used anywhere and seems useless anyway, we can
just drop it entirely. This appears to fix the issue on my HP ZBook with
an AMD WX4150.

Signed-off-by: Lyude Paul &lt;lyude@redhat.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Drop reusing drm connector for MST</title>
<updated>2018-11-07T23:20:56+00:00</updated>
<author>
<name>Jerry (Fangzhi) Zuo</name>
<email>Jerry.Zuo@amd.com</email>
</author>
<published>2018-10-30T18:37:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0e6613e46fed29316f33acf86e1d1568288638b5'/>
<id>0e6613e46fed29316f33acf86e1d1568288638b5</id>
<content type='text'>
[why]
It is not safe to keep existing connector while entire topology
has been removed. Could lead potential impact to uapi.
Entirely unregister all the connectors on the topology,
and use a new set of connectors when the topology is plugged back
on.

[How]
Remove the drm connector entirely each time when the
corresponding MST topology is gone.
When hotunplug a connector (e.g., DP2)
1. Remove connector from userspace.
2. Drop it's reference.
When hotplug back on:
1. Detect new topology, and create new connectors.
2. Notify userspace with sysfs hotplug event.
3. Reprobe new connectors, and reassign CRTC from old (e.g., DP2)
to new (e.g., DP3) connector.

Signed-off-by: Jerry (Fangzhi) Zuo &lt;Jerry.Zuo@amd.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[why]
It is not safe to keep existing connector while entire topology
has been removed. Could lead potential impact to uapi.
Entirely unregister all the connectors on the topology,
and use a new set of connectors when the topology is plugged back
on.

[How]
Remove the drm connector entirely each time when the
corresponding MST topology is gone.
When hotunplug a connector (e.g., DP2)
1. Remove connector from userspace.
2. Drop it's reference.
When hotplug back on:
1. Detect new topology, and create new connectors.
2. Notify userspace with sysfs hotplug event.
3. Reprobe new connectors, and reassign CRTC from old (e.g., DP2)
to new (e.g., DP3) connector.

Signed-off-by: Jerry (Fangzhi) Zuo &lt;Jerry.Zuo@amd.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Cleanup MST non-atomic code workaround</title>
<updated>2018-11-07T23:20:49+00:00</updated>
<author>
<name>Jerry (Fangzhi) Zuo</name>
<email>Jerry.Zuo@amd.com</email>
</author>
<published>2018-10-30T18:28:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8be17ac95f8451b51f636622d8d4b8674334f468'/>
<id>8be17ac95f8451b51f636622d8d4b8674334f468</id>
<content type='text'>
[why]
It is not correct to touch aconnector within atomic_check.

[How]
It was added as workaround before, and no longer needed.

Signed-off-by: Jerry (Fangzhi) Zuo &lt;Jerry.Zuo@amd.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[why]
It is not correct to touch aconnector within atomic_check.

[How]
It was added as workaround before, and no longer needed.

Signed-off-by: Jerry (Fangzhi) Zuo &lt;Jerry.Zuo@amd.com&gt;
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Reviewed-by: Lyude Paul &lt;lyude@redhat.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/display/dce11: only enable FBC when selected</title>
<updated>2018-11-06T21:46:12+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2018-11-02T15:54:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5822e9539dc11721b53d74accd4c091b982011d0'/>
<id>5822e9539dc11721b53d74accd4c091b982011d0</id>
<content type='text'>
Causes a black screen on a Stoney laptop.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=108577
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Causes a black screen on a Stoney laptop.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=108577
Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/display/dm: handle FBC dc feature parameter</title>
<updated>2018-11-06T21:45:56+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2018-11-06T20:19:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=04b94af4e348acc52546b9b19c933575f26589a1'/>
<id>04b94af4e348acc52546b9b19c933575f26589a1</id>
<content type='text'>
Set the dc_config properly when the option is enabled.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Set the dc_config properly when the option is enabled.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/display/dc: add FBC to dc_config</title>
<updated>2018-11-06T21:45:33+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2018-11-06T20:10:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ce2127c462d9d1c0832f088b23158420e87e71a0'/>
<id>ce2127c462d9d1c0832f088b23158420e87e71a0</id>
<content type='text'>
Add FBC to the list of features that can be enabled from the DM.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add FBC to the list of features that can be enabled from the DM.

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amdgpu/display: check if fbc is available in set_static_screen_control (v2)</title>
<updated>2018-11-06T21:45:08+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2018-11-02T15:51:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=689e7b34234e29e5168894b27b752a4e16ef08c4'/>
<id>689e7b34234e29e5168894b27b752a4e16ef08c4</id>
<content type='text'>
The value is dependent on whether fbc is available.

v2: only check if num_pipes is valid

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The value is dependent on whether fbc is available.

v2: only check if num_pipes is valid

Reviewed-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Stop leaking planes</title>
<updated>2018-11-06T21:25:28+00:00</updated>
<author>
<name>Harry Wentland</name>
<email>harry.wentland@amd.com</email>
</author>
<published>2018-10-07T14:01:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=02680efbb10be0d2c867fe722ae23d588f6bebef'/>
<id>02680efbb10be0d2c867fe722ae23d588f6bebef</id>
<content type='text'>
[Why]
drm_plane_cleanup does not free the plane.

[How]
Call drm_primary_helper_destroy which will also free the plane.

Signed-off-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[Why]
drm_plane_cleanup does not free the plane.

[How]
Call drm_primary_helper_destroy which will also free the plane.

Signed-off-by: Harry Wentland &lt;harry.wentland@amd.com&gt;
Acked-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>drm/amd/display: Fix misleading buffer information</title>
<updated>2018-11-06T21:24:42+00:00</updated>
<author>
<name>Shaokun Zhang</name>
<email>zhangshaokun@hisilicon.com</email>
</author>
<published>2018-11-05T10:33:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8ed4ec32d5b1f04a641978322a38a8d7089553bb'/>
<id>8ed4ec32d5b1f04a641978322a38a8d7089553bb</id>
<content type='text'>
RETIMER_REDRIVER_INFO shows the buffer as a decimal value with a '0x'
prefix, which is somewhat misleading.

Fix it to print hexadecimal, as was intended.

Fixes: 2f14bc89("drm/amd/display: add retimer log for HWQ tuning use.")
Cc: Charlene Liu &lt;charlene.liu@amd.com&gt;
Cc: Dmytro Laktyushkin &lt;Dmytro.Laktyushkin@amd.com&gt;
Signed-off-by: Shaokun Zhang &lt;zhangshaokun@hisilicon.com&gt;
Reviewed-by: Leo Li &lt;sunpeng.li@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
RETIMER_REDRIVER_INFO shows the buffer as a decimal value with a '0x'
prefix, which is somewhat misleading.

Fix it to print hexadecimal, as was intended.

Fixes: 2f14bc89("drm/amd/display: add retimer log for HWQ tuning use.")
Cc: Charlene Liu &lt;charlene.liu@amd.com&gt;
Cc: Dmytro Laktyushkin &lt;Dmytro.Laktyushkin@amd.com&gt;
Signed-off-by: Shaokun Zhang &lt;zhangshaokun@hisilicon.com&gt;
Reviewed-by: Leo Li &lt;sunpeng.li@amd.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "drm/amd/display: set backlight level limit to 1"</title>
<updated>2018-11-06T21:23:58+00:00</updated>
<author>
<name>Alex Deucher</name>
<email>alexander.deucher@amd.com</email>
</author>
<published>2018-11-06T21:06:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=63088da9472854408ae5d7c47bd011daf9e1a81b'/>
<id>63088da9472854408ae5d7c47bd011daf9e1a81b</id>
<content type='text'>
This reverts commit 0cafc82fae41531b0162150f9a97f2c74f97118f.

This breaks some apps that assume 0 is minimum brightness.

Revert for 4.20.  This is fixed properly for drm-next/4.21 in:
"drm/amd: Don't fail on backlight = 0"
However, that patch depends on more extensive changes to the
backlight interface which are too invasive for -fixes.

Fixes: Bugzilla: https://bugs.freedesktop.org/108668
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 0cafc82fae41531b0162150f9a97f2c74f97118f.

This breaks some apps that assume 0 is minimum brightness.

Revert for 4.20.  This is fixed properly for drm-next/4.21 in:
"drm/amd: Don't fail on backlight = 0"
However, that patch depends on more extensive changes to the
backlight interface which are too invasive for -fixes.

Fixes: Bugzilla: https://bugs.freedesktop.org/108668
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
