A mirror of the official Linux kernel repository just in case
Go to file
Ville Syrjälä 4c8d465104 drm/i915: Reorder hpd init vs. display resume
Currently we call .hpd_irq_setup() directly just before display
resume, and follow it with another call via intel_hpd_init()
just afterwards. Assuming the hpd pins are marked as enabled
during the open-coded call these two things do exactly the
same thing (ie. enable HPD interrupts). Which even makes sense
since we definitely need working HPD interrupts for MST sideband
during the display resume.

So let's nuke the open-coded call and move the intel_hpd_init()
call earlier. However we need to leave the poll_init_work stuff
behind after the display resume as that will trigger display
detection while we're resuming. We don't want that trampling over
the display resume process. To make this a bit more symmetric
we turn this into a intel_hpd_poll_{enable,disable}() pair.
So we end up with the following transformation:
intel_hpd_poll_init() -> intel_hpd_poll_enable()
lone intel_hpd_init() -> intel_hpd_init()+intel_hpd_poll_disable()
.hpd_irq_setup()+resume+intel_hpd_init() -> intel_hpd_init()+resume+intel_hpd_poll_disable()

If we really would like to prevent all *long* HPD processing during
display resume we'd need some kind of software mechanism to simply
ignore all long HPDs. Currently we appear to have that just for
fbdev via ifbdev->hpd_suspended. Since we aren't exploding left and
right all the time I guess that's mostly sufficient.

For a bit of history on this, we first got a mechanism to block
hotplug processing during suspend in commit 15239099d7 ("drm/i915:
enable irqs earlier when resuming") on account of moving the irq enable
earlier. This then got removed in commit 50c3dc970a ("drm/fb-helper:
Fix hpd vs. initial config races") because the fdev initial config
got pushed to a later point. The second ad-hoc hpd_irq_setup() for
resume was added in commit 0e32b39cee ("drm/i915: add DP 1.2 MST
support (v0.7)") to be able to do MST sideband during the resume.
And finally we got a partial resurrection of the hpd blocking
mechanism in commit e8a8fedd57 ("drm/i915: Block fbdev HPD
processing during suspend"), but this time it only prevent fbdev
from handling hpd while resuming.

v2: Leave the poll_init_work behind
v3: Remove the extra intel_hpd_poll_disable() from display reset (Lyude)
    Add the missing intel_hpd_poll_disable() to display init (Imre)

Cc: Lyude Paul <lyude@redhat.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201013181137.30560-1-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
2020-10-20 20:18:32 +03:00
arch Misc fixes: 2020-09-06 10:28:00 -07:00
block block-5.9-2020-09-04 2020-09-04 13:04:51 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation Documentation/gpu: Add asynchronous flip documentation for i915 2020-09-28 14:12:49 +03:00
drivers drm/i915: Reorder hpd init vs. display resume 2020-10-20 20:18:32 +03:00
fs io_uring-5.9-2020-09-06 2020-09-06 12:10:27 -07:00
include drm/i915/jsl: Split EHL/JSL platform info and PCI ids 2020-10-14 09:31:34 +02:00
init init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Linux 5.9-rc4 2020-09-08 14:41:40 +10:00
lib lib: Revert use of fallthrough pseudo-keyword in lib/ 2020-08-24 14:17:44 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm xen: branch for v5.9-rc4 2020-09-06 09:59:27 -07:00
net net/packet: fix overflow in tpacket_rcv 2020-09-04 11:56:02 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts Merge branch 'akpm' (patches from Andrew) 2020-09-05 13:28:40 -07:00
security treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools perf tools fixes for v5.9: 2nd batch 2020-09-03 19:10:43 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.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: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
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 5.9-rc4 2020-09-08 14:41:40 +10:00
Makefile Livepatching changes for 5.9-rc5 2020-09-08 10:52:59 -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.