Hi
Am 19.03.24 um 11:08 schrieb Jani Nikula:
On Tue, 19 Mar 2024, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
Hi
Am 19.03.24 um 10:37 schrieb Maxime Ripard:
Hi,
On Tue, Mar 19, 2024 at 09:00:32AM +0100, Thomas Zimmermann wrote:
Implement polling for VGA and SIL164 connectors. Set the flag
DRM_CONNECTOR_POLL_DISCONNECT for each to detect the removal of the
monitor cable. Implement struct drm_connector_helper_funcs.detect_ctx
for each type of connector by testing for EDID data. The code for
both types of connectors is identical for now. Maybe this can later
become a common helper function for various drivers.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/ast/ast_mode.c | 36 ++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 71cc681d6188f..f740b8706a38b 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1344,8 +1344,24 @@ static int ast_crtc_init(struct drm_device *dev)
* VGA Connector
*/
+static int ast_vga_connector_helper_detect_ctx(struct drm_connector *connector,
+ struct drm_modeset_acquire_ctx *ctx,
+ bool force)
+{
+ enum drm_connector_status status = connector_status_disconnected;
+ const struct drm_edid *edid;
+
+ edid = drm_edid_read(connector);
+ if (edid)
+ status = connector_status_connected;
+ drm_edid_free(edid);
+
+ return status;
+}
+
Yeah, I think it would be worth turning it into a helper. We have a
number of drivers using some variation of that already
(display-connector, loongson).
It's probably better to use drm_probe_ddc here too instead of parsing
and updating the EDID property each time we call detect.
I see. I'll update the patch accordingly. drm_probe_ddc() doesn't update
the property, which is probably better anyway.
The struct drm_edid based drm_edid_read() and friends do *not* parse the
EDID (apart from what's necessary to read the EDID) nor update the EDID
property. You need to call drm_edid_connector_update() separately for
that. This is by design.
Right. I'm confusing things. Sorry.
Best regards
Thomas
The struct edid based drm_get_edid() does parse and update the property,
and I think adding that was a mistake that a lot of drivers later
depended on, and couldn't be removed.
As a design consideration, IMO it's also a fine approach to read and
cache the EDID and update the property at ->detect, and then use
drm_edid_connector_add_modes() in ->get_modes to avoid re-reading the
EDID at that time. It's not uncommon to need stuff from the EDID between
those hooks.
BR,
Jani.
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
