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| author | Douglas Anderson <dianders@chromium.org> | 2024-05-14 10:20:55 -0700 |
|---|---|---|
| committer | Neil Armstrong <neil.armstrong@linaro.org> | 2024-05-15 22:59:13 +0200 |
| commit | 966e397e4f6032b73438f8d775756541513e7daf (patch) | |
| tree | 9fd539f701f750600033c00ac291bf03e530b52b /Documentation/gpu | |
| parent | 3b724909a380fddb44dfa0072fc459c698a52658 (diff) | |
| download | lwn-966e397e4f6032b73438f8d775756541513e7daf.tar.gz lwn-966e397e4f6032b73438f8d775756541513e7daf.zip | |
drm/mipi-dsi: Introduce mipi_dsi_*_write_seq_multi()
The current mipi_dsi_*_write_seq() macros are non-intutitive because
they contain a hidden "return" statement that will return out of the
_caller_ of the macro. Let's mark them as deprecated and instead
introduce some new macros that are more intuitive.
These new macros are less optimal when an error occurs but should
behave more optimally when there is no error. Specifically these new
macros cause smaller code to get generated and the code size savings
(less to fetch from RAM, less cache space used, less RAM used) are
important. Since the error case isn't something we need to optimize
for and these new macros are easier to understand and more flexible,
they should be used.
After converting to use these new functions, one example shows some
nice savings while also being easier to understand.
$ scripts/bloat-o-meter \
...after/panel-novatek-nt36672e.ko \
...ctx/panel-novatek-nt36672e.ko
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-988 (-988)
Function old new delta
nt36672e_1080x2408_60hz_init 6236 5248 -988
Total: Before=10651, After=9663, chg -9.28%
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20240514102056.v5.5.Ie94246c30fe95101e0e26dd5f96e976dbeb8f242@changeid
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240514102056.v5.5.Ie94246c30fe95101e0e26dd5f96e976dbeb8f242@changeid
Diffstat (limited to 'Documentation/gpu')
| -rw-r--r-- | Documentation/gpu/todo.rst | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index e2a0585915b3..2734b8a34541 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -494,6 +494,24 @@ Contact: Douglas Anderson <dianders@chromium.org> Level: Starter/Intermediate +Transition away from using mipi_dsi_*_write_seq() +------------------------------------------------- + +The macros mipi_dsi_generic_write_seq() and mipi_dsi_dcs_write_seq() are +non-intuitive because, if there are errors, they return out of the *caller's* +function. We should move all callers to use mipi_dsi_generic_write_seq_multi() +and mipi_dsi_dcs_write_seq_multi() macros instead. + +Once all callers are transitioned, the macros and the functions that they call, +mipi_dsi_generic_write_chatty() and mipi_dsi_dcs_write_buffer_chatty(), can +probably be removed. Alternatively, if people feel like the _multi() variants +are overkill for some use cases, we could keep the mipi_dsi_*_write_seq() +variants but change them not to return out of the caller. + +Contact: Douglas Anderson <dianders@chromium.org> + +Level: Starter + Core refactorings ================= |