Hi Jose,
On Wed, Apr 06, 2022 at 06:55:14PM +0200, José Expósito wrote:
> 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, which is less efficient.
>
> Avoid calling drm_detect_hdmi_monitor() and use drm_display_info.is_hdmi
> instead.
>
> 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:
How do you use ftrace to generate that?
> 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();
> cea_db_offsets.part.0();
> cea_db_is_hdmi_vsdb.part.0();
> 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();
> cea_db_offsets.part.0();
> cea_db_is_hdmi_vsdb.part.0();
> 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@xxxxxxxxx>
I think what you're hinting at in the cover letter would be best though:
we should just remove that caching entirely and use is_hdmi everywhere
Maxime
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