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51e039542b
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> |
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arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.editorconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
.rustfmt.toml | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
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.