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3b724909a3
Through a cooperative effort between Hsin-Yi Wang and Dmitry Baryshkov, we have realized the dev_err() in the mipi_dsi_*_write_seq() macros was causing quite a bit of bloat to the kernel. Let's hoist this call into drm_mipi_dsi.c by adding a "chatty" version of the functions that includes the print. While doing this, add a bit more comments to these macros making it clear that they print errors and also that they return out of _the caller's_ function. Without any changes to clients this gives a nice savings. Specifically the macro was inlined and thus the error report call was inlined into every call to mipi_dsi_dcs_write_seq() and mipi_dsi_generic_write_seq(). By using a call to a "chatty" function, the usage is reduced to one call in the chatty function and a function call at the invoking site. Building with my build system shows one example: $ scripts/bloat-o-meter \ .../before/panel-novatek-nt36672e.ko \ .../after/panel-novatek-nt36672e.ko add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-4404 (-4404) Function old new delta nt36672e_1080x2408_60hz_init 10640 6236 -4404 Total: Before=15055, After=10651, chg -29.25% Note that given the change in location of the print it's harder to include the "cmd" in the printout for mipi_dsi_dcs_write_seq() since, theoretically, someone could call the new chatty function with a zero-size array and it would be illegal to dereference data[0]. There's a printk format to print the whole buffer and this is probably more useful for debugging anyway. Given that we're doing this for mipi_dsi_dcs_write_seq(), let's also print the buffer for mipi_dsi_generic_write_seq() in the error case. It should be noted that the current consensus of DRM folks is that the mipi_dsi_*_write_seq() should be deprecated due to the non-intuitive return behavior. A future patch will formally mark them as deprecated and provide an alternative. Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> 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.v5.4.Id15fae80582bc74a0d4f1338987fa375738f45b9@changeid Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20240514102056.v5.4.Id15fae80582bc74a0d4f1338987fa375738f45b9@changeid
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.