[SRU][E/F/U][PATCH 0/2] drm/i915: Add new CNL PCH ID seen on a CML platform

[You-Sheng Yang]

From: You-Sheng Yang <vicamo at gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1852386

[Impact]
Some Comet Lake platforms got i915 call trace dump due to the lake of
support to its PCH id:

  [    2.999233] ------------[ cut here ]------------
  [    2.999238] eDP powered off while attempting aux channel
  communication.
  [    2.999338] WARNING: CPU: 2 PID: 296 at
  drivers/gpu/drm/i915/display/intel_dp.c:1148
  intel_dp_aux_xfer+0x767/0x900 [i915]
  [    2.999341] Modules linked in: i915(+) i2c_algo_bit drm_kms_helper
  syscopyarea sysfillrect sysimgblt fb_sys_fops drm r8169 ahci realtek
  libahci wmi video
  [    2.999350] CPU: 2 PID: 296 Comm: systemd-udevd Not tainted
  5.3.0-997-generic #201910072204
  [    2.999352] Hardware name: Dell Inc. OptiPlex 3280 AIO/, BIOS
  99.00.08 10/01/2019
  [    2.999391] RIP: 0010:intel_dp_aux_xfer+0x767/0x900 [i915]
  [    2.999394] Code: e8 ee b5 ff ff 84 c0 0f 85 ec f9 ff ff 48 8b 7d 80
  e8 5d b6 ff ff 84 c0 0f 85 db f9 ff ff 48 c7 c7 50 22 5d c0 e8 84 ea b5
  d1 <0f> 0b 48 8b 7d 80 48 8d 75 90 4c 8d ab a8 07 00 00 e8 63 b4 ff ff
  [    2.999398] RSP: 0018:ffffb7000040b5b8 EFLAGS: 00010286
  [    2.999400] RAX: 0000000000000000 RBX: ffff9bfa9dc20000 RCX:
  0000000000000396
  [    2.999402] RDX: 0000000000000001 RSI: 0000000000000082 RDI:
  0000000000000246
  [    2.999404] RBP: ffffb7000040b698 R08: 0000000000000396 R09:
  0000000000000019
  [    2.999406] R10: 000000000000072e R11: ffffb7000040b420 R12:
  0000000000000004
  [    2.999408] R13: ffff9bfa9fbca120 R14: ffff9bfa9dc20000 R15:
  ffff9bfa9dc207a8
  [    2.999410] FS:  00007f0d8613a680(0000) GS:ffff9bfaaec80000(0000)
  knlGS:0000000000000000
  [    2.999412] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [    2.999414] CR2: 00007ffca955ae58 CR3: 000000041e67e002 CR4:
  00000000003606e0
  [    2.999416] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
  0000000000000000
  [    2.999418] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
  0000000000000400
  [    2.999420] Call Trace:
  [    2.999425]  ? vprintk_default+0x29/0x50
  [    2.999464]  intel_dp_aux_transfer+0x15e/0x220 [i915]
  [    2.999472]  drm_dp_dpcd_access+0x72/0x110 [drm_kms_helper]
  [    2.999478]  drm_dp_dpcd_read+0x33/0xc0 [drm_kms_helper]
  [    2.999515]  intel_dp_read_dpcd+0x41/0x130 [i915]
  [    2.999551]  intel_edp_init_connector+0x136/0x540 [i915]
  [    2.999587]  intel_dp_init_connector+0x47f/0x870 [i915]
  [    2.999623]  intel_ddi_init+0x425/0x590 [i915]
  [    2.999660]  intel_setup_outputs+0x8e4/0xc60 [i915]

[Fix]
Two patches to be backported to have correct support:
* commit 37c92dc303dd "drm/i915: Add new CNL PCH ID seen on a CML
  platform" from drm-tip tree.
* patch "https://patchwork.freedesktop.org/patch/340416"

[Test Case]
1. Apply the patches to oem-osp1 kernel >= 1026 or Eoan/Focal generic
kernels.
2. Boot affected platforms with HDMI cable connected to an external
monitor.
3. Check if the monitor lights up when GDM service is started.

This was verified in to victim platforms.

[Regression Risk]
Low. This should affects only systems with matching PCH hw that is
currently affected by the regression to be fixed.

Imre Deak (2):
  drm/i915: Add new CNL PCH ID seen on a CML platform
  UBUNTU: SAUCE: drm/i915: Fix detection for a CMP-V PCH

 drivers/gpu/drm/i915/i915_drv.c | 5 +++++
 drivers/gpu/drm/i915/i915_drv.h | 1 +
 2 files changed, 6 insertions(+)

-- 
2.20.1