On Mon, 05 Aug 2024, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> The VGA-BMC connector selects the VGA output if a display has been
> attached to the physical connector. Otherwise it selects the BMC
> output. In any case, the connector status is set to 'detected', so
> that the userspace compositor displays to it.
>
> Depending on the setting, the connector's display modes either come
> from the VGA monitor's EDID or from an internal list of BMC-compatible
> modes.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
> drivers/gpu/drm/mgag200/mgag200_vga_bmc.c | 50 ++++++++++++++++++++++-
> 1 file changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mgag200/mgag200_vga_bmc.c b/drivers/gpu/drm/mgag200/mgag200_vga_bmc.c
> index b6b90632b3c6..3a958c3587ac 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_vga_bmc.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_vga_bmc.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-only
>
> #include <drm/drm_atomic_helper.h>
> +#include <drm/drm_edid.h>
> #include <drm/drm_modeset_helper_vtables.h>
> #include <drm/drm_probe_helper.h>
>
> @@ -11,9 +12,54 @@ static const struct drm_encoder_funcs mgag200_dac_encoder_funcs = {
> .destroy = drm_encoder_cleanup
> };
>
> +static int mgag200_vga_bmc_connector_helper_get_modes(struct drm_connector *connector)
> +{
> + struct mga_device *mdev = to_mga_device(connector->dev);
> + const struct mgag200_device_info *minfo = mdev->info;
> + int count;
> +
> + count = drm_connector_helper_get_modes(connector);
> +
> + if (!count) {
> + /*
> + * There's no EDID data without a connected monitor. Set BMC-
> + * compatible modes in this case. The XGA default resolution
> + * should work well for all BMCs.
> + */
> + count = drm_add_modes_noedid(connector, minfo->max_hdisplay, minfo->max_vdisplay);
> + if (count)
> + drm_set_preferred_mode(connector, 1024, 768);
> + }
> +
> + return count;
> +}
> +
> +/*
> + * There's no monitor connected if the DDC did not return an EDID. Still
> + * return 'connected' as there's always a BMC. Incrementing the connector's
> + * epoch counter triggers an update of the related properties.
> + */
> +static int mgag200_vga_bmc_connector_helper_detect_ctx(struct drm_connector *connector,
> + struct drm_modeset_acquire_ctx *ctx,
> + bool force)
> +{
> + enum drm_connector_status old_status, status;
> +
> + if (connector->edid_blob_ptr)
This is now the only place outside of drm_edid.c that uses edid_blob_ptr
for anything.
Seems like you're using it as a proxy for "had a display connected".
I wish it could be kept private to the EDID code.
BR,
Jani.
> + old_status = connector_status_connected;
> + else
> + old_status = connector_status_disconnected;
> +
> + status = drm_connector_helper_detect_from_ddc(connector, ctx, force);
> +
> + if (status != old_status)
> + ++connector->epoch_counter;
> + return connector_status_connected;
> +}
> +
> static const struct drm_connector_helper_funcs mgag200_vga_connector_helper_funcs = {
> - .get_modes = drm_connector_helper_get_modes,
> - .detect_ctx = drm_connector_helper_detect_from_ddc
> + .get_modes = mgag200_vga_bmc_connector_helper_get_modes,
> + .detect_ctx = mgag200_vga_bmc_connector_helper_detect_ctx,
> };
>
> static const struct drm_connector_funcs mgag200_vga_connector_funcs = {
--
Jani Nikula, Intel
