Re: [PATCH v2 5/8] drm: Use new mode_valid() helpers in connector probe helper

From: Daniel Vetter
Date: Wed May 10 2017 - 04:01:16 EST


On Tue, May 09, 2017 at 06:00:12PM +0100, Jose Abreu wrote:
> This changes the connector probe helper function to use the new
> encoder->mode_valid() and crtc->mode_valid() helper callbacks to
> validate the modes.
>
> The new callbacks are optional so the behaviour remains the same
> if they are not implemented. If they are, then the code loops
> through all the connector's encodersXcrtcs and calls the
> callback.
>
> If at least a valid encoderXcrtc combination is found which
> accepts the mode then the function returns MODE_OK.
>
> Signed-off-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
> Cc: Carlos Palminha <palminha@xxxxxxxxxxxx>
> Cc: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxx>
> Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Cc: Archit Taneja <architt@xxxxxxxxxxxxxx>
> ---
>
> Changes v1->v2:
> - Use new helpers suggested by Ville
> - Change documentation (Daniel)
>
> drivers/gpu/drm/drm_probe_helper.c | 60 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 57 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 1b0c14a..de47413 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -39,6 +39,8 @@
> #include <drm/drm_fb_helper.h>
> #include <drm/drm_edid.h>
>
> +#include "drm_crtc_internal.h"
> +
> /**
> * DOC: output probing helper overview
> *
> @@ -80,6 +82,54 @@
> return MODE_OK;
> }
>
> +static enum drm_mode_status
> +drm_mode_validate_connector(struct drm_connector *connector,
> + struct drm_display_mode *mode)
> +{
> + struct drm_device *dev = connector->dev;
> + uint32_t *ids = connector->encoder_ids;
> + enum drm_mode_status ret = MODE_OK;
> + unsigned int i;
> +
> + /* Step 1: Validate against connector */
> + ret = drm_connector_mode_valid(connector, mode);
> + if (ret != MODE_OK)
> + return ret;
> +
> + /* Step 2: Validate against encoders and crtcs */
> + for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
> + struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
> + struct drm_crtc *crtc;
> +
> + if (!encoder)
> + continue;
> +
> + ret = drm_encoder_mode_valid(encoder, mode);
> + if (ret != MODE_OK) {
> + /* No point in continuing for crtc check as this encoder
> + * will not accept the mode anyway. If all encoders
> + * reject the mode then, at exit, ret will not be
> + * MODE_OK. */
> + continue;
> + }

One thing I've forgotten the last time around: Please also check
bridge->mode_valid here. The encoder->bridge mapping is fixed.

Otherwise I think this looks good.
-Daniel

> +
> + drm_for_each_crtc(crtc, dev) {
> + if (!drm_encoder_crtc_ok(encoder, crtc))
> + continue;
> +
> + ret = drm_crtc_mode_valid(crtc, mode);
> + if (ret == MODE_OK) {
> + /* If we get to this point there is at least
> + * one combination of encoder+crtc that works
> + * for this mode. Lets return now. */
> + return ret;
> + }
> + }
> + }
> +
> + return ret;
> +}
> +
> static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
> {
> struct drm_cmdline_mode *cmdline_mode;
> @@ -284,7 +334,11 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
> * - drm_mode_validate_flag() checks the modes against basic connector
> * capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
> * - the optional &drm_connector_helper_funcs.mode_valid helper can perform
> - * driver and/or hardware specific checks
> + * driver and/or sink specific checks
> + * - the optional &drm_crtc_helper_funcs.mode_valid and
> + * &drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
> + * source specific checks which are also enforced by the modeset/atomic
> + * helpers
> *
> * 5. Any mode whose status is not OK is pruned from the connector's modes list,
> * accompanied by a debug message indicating the reason for the mode's
> @@ -428,8 +482,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
> if (mode->status == MODE_OK)
> mode->status = drm_mode_validate_flag(mode, mode_flags);
>
> - if (mode->status == MODE_OK && connector_funcs->mode_valid)
> - mode->status = connector_funcs->mode_valid(connector,
> + if (mode->status == MODE_OK)
> + mode->status = drm_mode_validate_connector(connector,
> mode);
> }
>
> --
> 1.9.1
>
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch