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Vivek Kasireddy 0aa93f54f4 drm/i915/tc: Don't default disconnected legacy Type-C ports to TBT mode (v2)
Commit 30e114ef4b ("drm/i915/tc: Check for DP-alt, legacy sinks before
taking PHY ownership") defaults any disconnected Type-C ports to TBT-alt
mode which presents a problem (which could most likely result in a system
hang) when userspace forces a modeset on a Type-C port that is wired for
legacy HDMI. The following warning is seen when Weston forces a modeset
on a disconnected legacy Type-C port (HDMI) on a TGL based Gigabyte system:
(https://www.gigabyte.com/Mini-PcBarebone/GB-BSi3-1115G4-rev-10#ov)

Missing case (clock == 173000)
WARNING: CPU: 1 PID: 438 at drivers/gpu/drm/i915/display/intel_ddi.c:245
icl_ddi_tc_enable_clock.cold+0x16a/0x1cf [i915]
CPU: 1 PID: 438 Comm: kworker/u8:3 Tainted: G     U  W   E
5.18.0-rc5-drm-tip+ #20
Hardware name: GIGABYTE GB-BSi3-1115G4/GB-BSi3-1115G4, BIOS F9
10/16/2021
Workqueue: i915_modeset intel_atomic_commit_work [i915]
RIP: 0010:icl_ddi_tc_enable_clock.cold+0x16a/0x1cf [i915]
Code: 74 6c 7f 10 81 fd d0 78 02 00 74 6d 81 fd b0 1e 04 00 74 70 48 63
d5 48 c7 c6 c0 7b ab c0 48 c7 c7 20 75 ab c0 e8 b8 b5 c1 f0 <0f> 0b 45
31 ed e9 fb fe ff ff 49 63 d5
 48 c7 c6 80 7b ab c0 48 c7
RSP: 0018:ffff8882522c78f0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000027 RSI: 0000000000000004 RDI: ffffed104a458f10
RBP: 0000000000011558 R08: ffffffffb078de4e R09: ffff888269ca748b
R10: ffffed104d394e91 R11: 0000000000000000 R12: ffff888255a318f8
R13: 0000000000000002 R14: ffff888255a30000 R15: ffff88823ef00348
FS:  0000000000000000(0000) GS:ffff888269c80000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7afa42000 CR3: 0000000255c02004 CR4: 00000000007706e0
PKRU: 55555554
Call Trace:
<TASK>
intel_ddi_pre_enable.cold+0x96/0x5bf [i915]
intel_encoders_pre_enable+0x10e/0x140 [i915]
hsw_crtc_enable+0x207/0x99d [i915]
? ilk_crtc_enable.cold+0x2a/0x2a [i915]
? prepare_to_wait_exclusive+0x120/0x120
intel_enable_crtc+0x9a/0xf0 [i915]
skl_commit_modeset_enables+0x466/0x820 [i915]
? intel_commit_modeset_enables+0xd0/0xd0 [i915]
? intel_mbus_dbox_update+0x1ed/0x250 [i915]
intel_atomic_commit_tail+0xf2d/0x3040 [i915]
_raw_spin_lock_irqsave+0x87/0xe0
_raw_read_unlock_irqrestore+0x40/0x40
__update_load_avg_cfs_rq+0x70/0x5c0
__i915_sw_fence_complete+0x85/0x3b0 [i915]
? intel_get_crtc_new_encoder+0x190/0x190 [i915]
? sysvec_irq_work+0x13/0x90
? asm_sysvec_irq_work+0x12/0x20
? _raw_spin_lock_irq+0x82/0xd0
? read_word_at_a_time+0xe/0x20
? process_one_work+0x393/0x690
process_one_work+0x393/0x690
worker_thread+0x2b7/0x620
? process_one_work+0x690/0x690
kthread+0x15a/0x190
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30

Continuing with the modeset without setting the DDI clock results in
more warnings and eventually a system hang. This does not seem to
happen with disconnected legacy or DP-alt DP ports because the clock
rate defaults to 162000 (which is a valid TBT clock) during the link
training process. Therefore, to fix this issue, this patch avoids
setting disconnected Type-C legacy ports to TBT-alt mode which prevents
the selection of TBT PLL when a modeset is forced.

v2: (Imre)
- Retain the check for legacy hotplug live status to account for
incorrect VBTs.

Cc: Imre Deak <imre.deak@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220526001939.4031112-2-vivek.kasireddy@intel.com
2022-05-31 19:55:16 +03:00
arch Merge drm/drm-next into drm-intel-next 2022-04-26 16:44:31 +03:00
block for-5.18/block-2022-04-01 2022-04-01 16:20:00 -07:00
certs Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
crypto for-5.18/64bit-pi-2022-03-25 2022-03-26 12:01:35 -07:00
Documentation Merge drm/drm-next into drm-intel-next 2022-04-26 16:44:31 +03:00
drivers drm/i915/tc: Don't default disconnected legacy Type-C ports to TBT mode (v2) 2022-05-31 19:55:16 +03:00
fs Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
include drm/i915: Add first set of DG2 PCI IDs 2022-04-27 16:17:45 -07:00
init Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
ipc fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
kernel Merge drm/drm-next into drm-misc-next 2022-04-18 20:46:55 +01:00
lib Driver core changes for 5.18-rc2 2022-04-10 09:55:09 -10:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm - Allow the compiler to optimize away unused percpu accesses and change 2022-04-10 06:56:46 -10:00
net NFS client bugfixes for Linux 5.18 2022-04-08 07:39:17 -10:00
samples vfio/mdev: Remove mdev_parent_ops 2022-04-21 07:36:56 -04:00
scripts modpost: restore the warning message for missing symbol versions 2022-04-03 03:11:51 +09:00
security hardening updates for v5.18-rc1-fix1 2022-03-31 11:43:01 -07:00
sound sound fixes for 5.18-rc1 2022-04-01 10:32:46 -07:00
tools - Fix the MSI message data struct definition 2022-04-10 07:12:27 -10:00
usr Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
virt KVM: Remove dirty handling from gfn_to_pfn_cache completely 2022-04-02 05:34:41 -04:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Vasily Averin's email address 2022-04-08 14:20:36 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS drm-misc-next for 5.19: 2022-04-12 17:44:27 +10:00
Makefile Linux 5.18-rc2 2022-04-10 14:21:36 -10:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.