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author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-01-04 07:53:36 +0100 |
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committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-01-05 16:21:35 +0100 |
commit | df7d678bea8ba8904bdb293c8e96aa9488f7dbee (patch) | |
tree | a3b9ad6d31b65713b25062e236e8dd2ac24d3fd5 /include | |
parent | 4cba68507cf58db99752cf79198beb4a85a9f8ce (diff) | |
download | op-kernel-dev-df7d678bea8ba8904bdb293c8e96aa9488f7dbee.zip op-kernel-dev-df7d678bea8ba8904bdb293c8e96aa9488f7dbee.tar.gz |
drm/docs: more leftovers from the big vtable documentation pile
Another pile of vfuncs from the old gpu.tmpl xml documentation that
I've forgotten to delete. I spotted a few more things to
clarify/extend in the new kerneldoc while going through this once
more.
v2: Spelling fixes (Thierry).
v3: More spelling fixes and use Thierry's proposal to clarify why
drivers need to validate modes both in ->mode_fixup and ->mode_valid.
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/drm/drm_modeset_helper_vtables.h | 44 |
1 files changed, 41 insertions, 3 deletions
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index 29e0dc5..a126a0d 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -131,6 +131,20 @@ struct drm_crtc_helper_funcs { * Atomic drivers which need to inspect and adjust more state should * instead use the @atomic_check callback. * + * Also beware that neither core nor helpers filter modes before + * passing them to the driver: While the list of modes that is + * advertised to userspace is filtered using the connector's + * ->mode_valid() callback, neither the core nor the helpers do any + * filtering on modes passed in from userspace when setting a mode. It + * is therefore possible for userspace to pass in a mode that was + * previously filtered out using ->mode_valid() or add a custom mode + * that wasn't probed from EDID or similar to begin with. Even though + * this is an advanced feature and rarely used nowadays, some users rely + * on being able to specify modes manually so drivers must be prepared + * to deal with it. Specifically this means that all drivers need not + * only validate modes in ->mode_valid() but also in ->mode_fixup() to + * make sure invalid modes passed in from userspace are rejected. + * * RETURNS: * * True if an acceptable configuration is possible, false if the modeset @@ -188,7 +202,9 @@ struct drm_crtc_helper_funcs { * This callback is used by the legacy CRTC helpers to set a new * framebuffer and scanout position. It is optional and used as an * optimized fast-path instead of a full mode set operation with all the - * resulting flickering. Since it can't update other planes it's + * resulting flickering. If it is not present + * drm_crtc_helper_set_config() will fall back to a full modeset, using + * the ->mode_set() callback. Since it can't update other planes it's * incompatible with atomic modeset support. * * This callback is only used by the CRTC helpers and deprecated. @@ -439,6 +455,20 @@ struct drm_encoder_helper_funcs { * Atomic drivers which need to inspect and adjust more state should * instead use the @atomic_check callback. * + * Also beware that neither core nor helpers filter modes before + * passing them to the driver: While the list of modes that is + * advertised to userspace is filtered using the connector's + * ->mode_valid() callback, neither the core nor the helpers do any + * filtering on modes passed in from userspace when setting a mode. It + * is therefore possible for userspace to pass in a mode that was + * previously filtered out using ->mode_valid() or add a custom mode + * that wasn't probed from EDID or similar to begin with. Even though + * this is an advanced feature and rarely used nowadays, some users rely + * on being able to specify modes manually so drivers must be prepared + * to deal with it. Specifically this means that all drivers need not + * only validate modes in ->mode_valid() but also in ->mode_fixup() to + * make sure invalid modes passed in from userspace are rejected. + * * RETURNS: * * True if an acceptable configuration is possible, false if the modeset @@ -640,8 +670,16 @@ struct drm_connector_helper_funcs { * In this function drivers then parse the modes in the EDID and add * them by calling drm_add_edid_modes(). But connectors that driver a * fixed panel can also manually add specific modes using - * drm_mode_probed_add(). Finally drivers that support audio probably - * want to update the ELD data, too, using drm_edid_to_eld(). + * drm_mode_probed_add(). Drivers which manually add modes should also + * make sure that the @display_info, @width_mm and @height_mm fields of the + * struct #drm_connector are filled in. + * + * Virtual drivers that just want some standard VESA mode with a given + * resolution can call drm_add_modes_noedid(), and mark the preferred + * one using drm_set_preferred_mode(). + * + * Finally drivers that support audio probably want to update the ELD + * data, too, using drm_edid_to_eld(). * * This function is only called after the ->detect() hook has indicated * that a sink is connected and when the EDID isn't overridden through |