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Ville Syrjälä 51e039542b drm/i915/dsb: Allow intel_dsb_chain() to use DSB_WAIT_FOR_VBLANK
Allow intel_dsb_chain() to start the chained DSB
at start of the undelaye vblank. This is slightly
more involved than simply setting the bit as we
must use the DEwake mechanism to eliminate pkgC
latency.

And DSB_ENABLE_DEWAKE itself is problematic in that
it allows us to configure just a single scanline,
and if the current scanline is already past that
DSB_ENABLE_DEWAKE won't do anything, rendering the
whole thing moot.

The current workaround involves checking the pipe's current
scanline with the CPU, and if it looks like we're about to
miss the configured DEwake scanline we set DSB_FORCE_DEWAKE
to immediately assert DEwake. This is somewhat racy since the
hardware is making progress all the while we're checking it on
the CPU.

We can make things less racy by chaining two DSBs and handling
the DSB_FORCE_DEWAKE stuff entirely without CPU involvement:
1. CPU starts the first DSB immediately
2. First DSB configures the second DSB, including its dewake_scanline
3. First DSB starts the second w/ DSB_WAIT_FOR_VBLANK
4. First DSB asserts DSB_FORCE_DEWAKE
5. First DSB waits until we're outside the dewake_scanline-vblank_start
   window
6. First DSB deasserts DSB_FORCE_DEWAKE

That will guarantee that the we are fully awake when the second
DSB starts to actually execute.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240624191032.27333-12-ville.syrjala@linux.intel.com
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
2024-08-29 14:54:03 +03:00
arch Linux 6.11-rc5 2024-08-27 14:09:45 +02:00
block block: Read max write zeroes once for __blkdev_issue_write_zeroes() 2024-08-19 09:48:59 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation Linux 6.11-rc5 2024-08-27 14:09:45 +02:00
drivers drm/i915/dsb: Allow intel_dsb_chain() to use DSB_WAIT_FOR_VBLANK 2024-08-29 14:54:03 +03:00
fs Linux 6.11-rc5 2024-08-27 14:09:45 +02:00
include Merge drm/drm-next into drm-intel-next 2024-08-27 17:06:28 -04:00
init Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
io_uring io_uring/kbuf: sanitize peek buffer setup 2024-08-21 07:16:38 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel Linux 6.11-rc5 2024-08-27 14:09:45 +02:00
lib bcachefs fixes for 6.11-rc4 2024-08-17 09:46:10 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 16 hotfixes. All except one are for MM. 10 of these are cc:stable and 2024-08-17 19:50:16 -07:00
net NFS Client Bugfixes for Linux 6.11-rc 2024-08-24 09:03:25 +08:00
rust Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
samples treewide: remove unnecessary <linux/version.h> inclusion 2024-08-12 18:36:44 +09:00
scripts Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
security KEYS: trusted: dcp: fix leak of blob encryption key 2024-08-15 22:01:14 +03:00
sound Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
tools Including fixes from bluetooth and netfilter. 2024-08-23 07:47:01 +08:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap mailmap: update entry for David Heidelberg 2024-08-07 18:33:56 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Linux 6.11-rc5 2024-08-27 14:09:45 +02:00
Makefile Linux 6.11-rc5 2024-08-25 19:07:11 +12:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.