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8c5dbb5039
Currently we can't change MBUS join status without doing a modeset,
because we are lacking mechanism to synchronize those with vblank.
However then this means that we can't do a fastset, if there is a need
to change MBUS join state. Fix that by implementing such change.
We already call correspondent check and update at pre_plane dbuf update,
so the only thing left is to have a non-modeset version of that.
If active pipes stay the same then fastset is possible and only MBUS
join state/ddb allocation updates would be committed.
The full mbus/cdclk sequence will look as follows:
1. disable pipes
2. increase cdclk if necessary
2.1 reprogram cdclk
2.2 update dbuf tracker value
3. enable mbus joining if necessary
3.1 update mbus_ctl
3.2 update dbuf tracker value
4. reallocate dbuf for planes on active pipes
5. disable mbus joining if necessary
5.1 update dbuf tracker value
5.2 update mbus_ctl
6. enable pipes
7. decrease cdclk if necessary
7.1 update dbuf tracker value
7.2 reprogram cdclk
And in order to keep things in sync we need:
Step 2:
- mbus_join == old
- mdclk/cdclk ratio == new
Step 3:
- mbus_join == new
- mdclk/cdclk ratio == old when cdclk is changing in step 7
- mdclk/cdclk ratio == new when cdclk is changing in step 2
Step 5:
- mbus_join == new
- mdclk/cdclk ratio == old when cdclk is changing in step 7
- mdclk/cdclk ratio == new when cdclk is changing in step 2
Step 7:
- mbus_join == new
- mdclk/cdclk ratio == new
v2: - Removed redundant parentheses(Ville Syrjälä)
- Constified new_crtc_state in intel_mbus_joined_pipe(Ville Syrjälä)
- Removed pipe_select variable(Ville Syrjälä)
[v3: vsyrjala: Correctly sequence vs. cdclk updates,
properly describe the full sequence,
shuffle code around to make the diff more legible,
streamline a few things]
[v4: vsyrjala: Move the intel_cdclk_is_decreasing_later() stuff
to a separate patch]
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com> #v3
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Co-developed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240402155016.13733-13-ville.syrjala@linux.intel.com
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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.