On Thu, Feb 16, 2017 at 12:36:45PM +0200, Jani Nikula wrote:
> Handle debugfs override edid and firmware edid at the low level to
> transparently and completely replace the real edid. Previously, we
> practically only used the modes from the override EDID, and none of the
> other data. This also prevents actual EDID reads when the EDID is to be
> overridden, but retains the DDC probe.
Hmm. Isn't that a bad thing? If someone has broken DDC on their cable or
somethign then the override EDID wouldn't be returned by drm_get_edid().
>
> FIXME: validate override edid, deduplicate firmware edid validation.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 15 +++++++++++++++
> drivers/gpu/drm/drm_probe_helper.c | 19 +------------------
> 2 files changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 362036360724..054e2d74eafc 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1309,6 +1309,10 @@ static void connector_bad_edid(struct drm_connector *connector,
> * level, drivers must make all reasonable efforts to expose it as an I2C
> * adapter and use drm_get_edid() instead of abusing this function.
> *
> + * The EDID may be overridden using debugfs override_edid or firmare EDID
> + * (drm_load_edid_firmware()), in this priority order. Having either of them
> + * bypasses actual EDID reads.
> + *
> * Return: Pointer to valid EDID or NULL if we couldn't find any.
> */
> struct edid *drm_do_get_edid(struct drm_connector *connector,
> @@ -1318,6 +1322,17 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
> {
> int i, j = 0, valid_extensions = 0;
> u8 *edid, *new;
> + struct edid *override = NULL;
> +
> + if (connector->override_edid)
> + override = drm_edid_duplicate((const struct edid *)
> + connector->edid_blob_ptr->data);
> +
> + if (!override)
> + override = drm_load_edid_firmware(connector);
> +
> + if (!IS_ERR_OR_NULL(override))
> + return override;
>
> if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
> return NULL;
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 358957118ca9..871326cbc465 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -199,8 +199,6 @@ drm_connector_detect(struct drm_connector *connector, bool force)
> * drm_mode_probed_add(). New modes start their life with status as OK.
> * Modes are added from a single source using the following priority order.
> *
> - * - debugfs 'override_edid' (used for testing only)
> - * - firmware EDID (drm_load_edid_firmware())
> * - &drm_connector_helper_funcs.get_modes vfunc
> * - if the connector status is connector_status_connected, standard
> * VESA DMT modes up to 1024x768 are automatically added
> @@ -305,22 +303,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
> goto prune;
> }
>
> - if (connector->override_edid) {
> - struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
> -
> - count = drm_add_edid_modes(connector, edid);
> - drm_edid_to_eld(connector, edid);
> - } else {
> - struct edid *edid = drm_load_edid_firmware(connector);
> - if (!IS_ERR_OR_NULL(edid)) {
> - drm_mode_connector_update_edid_property(connector, edid);
> - count = drm_add_edid_modes(connector, edid);
> - drm_edid_to_eld(connector, edid);
> - kfree(edid);
> - }
> - if (count == 0)
> - count = (*connector_funcs->get_modes)(connector);
> - }
> + count = (*connector_funcs->get_modes)(connector);
>
> if (count == 0 && connector->status == connector_status_connected)
> count = drm_add_modes_noedid(connector, 1024, 768);
> --
> 2.1.4
--
Ville Syrjälä
Intel OTC
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