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Once EDID is parsed, the monitor HDMI support information is cached in
drm_display_info.is_hdmi by drm_parse_hdmi_vsdb_video().
This driver calls drm_detect_hdmi_monitor() to receive the same
information and stores its own cached value in
vc4_hdmi_encoder.hdmi_monitor, which is less efficient.
Avoid calling drm_detect_hdmi_monitor() and use drm_display_info.is_hdmi
instead. This also allows to remove vc4_hdmi_encoder.hdmi_monitor.
drm_detect_hdmi_monitor() is called in vc4_hdmi_connector_detect() and
vc4_hdmi_connector_get_modes(). In both cases it is safe to rely on
drm_display_info.is_hdmi as shown by ftrace:
$ sudo trace-cmd record -p function_graph -l "vc4_hdmi_*" -l "drm_*"
vc4_hdmi_connector_detect:
vc4_hdmi_connector_detect() {
drm_get_edid() {
drm_connector_update_edid_property() {
drm_add_display_info() {
drm_reset_display_info();
drm_for_each_detailed_block.part.0();
drm_parse_cea_ext() {
drm_find_cea_extension();
drm_parse_hdmi_vsdb_video();
/* drm_display_info.is_hdmi is cached here */
}
}
}
}
/* drm_display_info.is_hdmi is used here */
}
vc4_hdmi_connector_get_modes:
vc4_hdmi_connector_get_modes() {
drm_get_edid() {
drm_connector_update_edid_property() {
drm_add_display_info() {
drm_reset_display_info();
drm_for_each_detailed_block.part.0();
drm_parse_cea_ext() {
drm_find_cea_extension();
drm_parse_hdmi_vsdb_video();
/* drm_display_info.is_hdmi is cached here */
}
}
}
}
/* drm_display_info.is_hdmi is used here */
drm_connector_update_edid_property();
}
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220420114500.187664-2-jose.exposito89@gmail.com
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 Restructured Text 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.