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Ville Syrjälä 49c55f7b03 drm/i915/hdmi: Turn DP++ TMDS output buffers back on in encoder->shutdown()
Looks like our VBIOS/GOP generally fail to turn the DP dual mode adater
TMDS output buffers back on after a reboot. This leads to a black screen
after reboot if we turned the TMDS output buffers off prior to reboot.
And if i915 decides to do a fastboot the black screen will persist even
after i915 takes over.

Apparently this has been a problem ever since commit b2ccb822d3 ("drm/i915:
Enable/disable TMDS output buffers in DP++ adaptor as needed") if one
rebooted while the display was turned off. And things became worse with
commit fe0f1e3bfd ("drm/i915: Shut down displays gracefully on reboot")
since now we always turn the display off before a reboot.

This was reported on a RKL, but I confirmed the same behaviour on my
SNB as well. So looks pretty universal.

Let's fix this by explicitly turning the TMDS output buffers back on
in the encoder->shutdown() hook. Note that this gets called after irqs
have been disabled, so the i2c communication with the DP dual mode
adapter has to be performed via polling (which the gmbus code is
perfectly happy to do for us).

We also need a bit of care in handling DDI encoders which may or may
not be set up for HDMI output. Specifically ddc_pin will not be
populated for a DP only DDI encoder, in which case we don't want to
call intel_gmbus_get_adapter(). We can handle that by simply doing
the dual mode adapter type check before calling
intel_gmbus_get_adapter().

Cc: <stable@vger.kernel.org> # v5.11+
Fixes: fe0f1e3bfd ("drm/i915: Shut down displays gracefully on reboot")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4371
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211029191802.18448-2-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
2021-11-01 14:15:18 +02:00
arch Linux 5.15-rc7 2021-10-28 14:59:38 +10:00
block block-5.15-2021-10-22 2021-10-22 17:42:13 -10:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation Merge tag 'drm-msm-next-2021-10-26' of https://gitlab.freedesktop.org/drm/msm into drm-next 2021-10-28 15:07:48 +10:00
drivers drm/i915/hdmi: Turn DP++ TMDS output buffers back on in encoder->shutdown() 2021-11-01 14:15:18 +02:00
fs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-10-24 09:36:06 -10:00
include Merge drm/drm-next into drm-intel-next 2021-10-29 13:40:45 +03:00
init bootconfig: init: Fix memblock leak in xbc_make_cmdline() 2021-10-10 22:27:40 -04:00
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2021-09-14 10:22:11 -07:00
kernel Linux 5.15-rc7 2021-10-28 14:59:38 +10:00
lib Linux 5.15-rc7 2021-10-28 14:59:38 +10:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm Linux 5.15-rc7 2021-10-28 14:59:38 +10:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2021-10-21 12:32:41 +01:00
samples samples/bpf: Relicense bpf_insn.h as GPL-2.0-only OR BSD-2-Clause 2021-09-29 16:03:55 +02:00
scripts Tracing fixes for 5.15: 2021-10-16 10:51:41 -07:00
security Merge branch 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-10-21 17:27:17 -10:00
sound ALSA: usb-audio: Fix microphone sound on Jieli webcam. 2021-10-19 08:07:01 +02:00
tools Networking fixes for 5.15-rc7, including fixes from netfilter, and can. 2021-10-21 15:36:50 -10:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: Remove tlbs_dirty 2021-09-23 11:01:12 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
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.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 Linux 5.15-rc7 2021-10-28 14:59:38 +10:00
Makefile Linux 5.15-rc7 2021-10-25 11:30:31 -07:00
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.