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Message-ID: <6913165B-FA17-4DED-B1D6-CA312B20576B@bootlin.com>
Date: Mon, 25 Nov 2024 10:19:49 +0000
From: Louis Chauvet <louis.chauvet@...tlin.com>
To: dri-devel@...ts.freedesktop.org, Jani Nikula <jani.nikula@...ux.intel.com>,
Maíra Canal <mairacanal@...eup.net>,
Haneen Mohammed <hamohammed.sa@...il.com>, Simona Vetter <simona@...ll.ch>,
Melissa Wen <melissa.srw@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>
CC: arthurgrillo@...eup.net, jeremie.dautheribes@...tlin.com,
miquel.raynal@...tlin.com, thomas.petazzoni@...tlin.com, seanpaul@...gle.com,
nicolejadeyee@...gle.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC v2 17/18] drm/vkms: Introduce config for connector EDID
Le 25 novembre 2024 09:45:04 UTC, Jani Nikula <jani.nikula@...ux.intel.com> a écrit :
>On Fri, 22 Nov 2024, Louis Chauvet <louis.chauvet@...tlin.com> wrote:
>> To properly test the EDID reading without using the DRM override, add an
>> option to configure the EDID for a connector.
>>
>> Signed-off-by: Louis Chauvet <louis.chauvet@...tlin.com>
>> ---
>> drivers/gpu/drm/vkms/vkms_config.c | 1 +
>> drivers/gpu/drm/vkms/vkms_config.h | 2 ++
>> drivers/gpu/drm/vkms/vkms_output.c | 37 ++++++++++++++++++++++++++++++++++---
>> 3 files changed, 37 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
>> index ac1a9658c5075c118d59da965ca3392355ccb2b2..1a1234d4f10fa8e5ea6bd649139ecc10c991f875 100644
>> --- a/drivers/gpu/drm/vkms/vkms_config.c
>> +++ b/drivers/gpu/drm/vkms/vkms_config.c
>> @@ -199,6 +199,7 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *v
>> xa_init_flags(&vkms_config_connector->possible_encoders, XA_FLAGS_ALLOC);
>> vkms_config_connector->type = DRM_MODE_CONNECTOR_VIRTUAL;
>> vkms_config_connector->status = connector_status_unknown;
>> + vkms_config_connector->edid_blob_len = 0;
>>
>> return vkms_config_connector;
>> }
>> diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
>> index bba56c9d8aeceac97a4339ef42ab663c5dc54e65..1220b16f6c98d1ebb0ae55d662a84fe25e1a6a02 100644
>> --- a/drivers/gpu/drm/vkms/vkms_config.h
>> +++ b/drivers/gpu/drm/vkms/vkms_config.h
>> @@ -112,6 +112,8 @@ struct vkms_config_connector {
>> struct xarray possible_encoders;
>> int type;
>> enum drm_connector_status status;
>> + char edid_blob[PAGE_SIZE];
>> + int edid_blob_len;
>>
>> /* Internal usage */
>> struct drm_connector *connector;
>> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
>> index fc6a0cdade0739b94820ed4e0924cf355137fe79..56590afb33d75465971d10a282040690840cdbee 100644
>> --- a/drivers/gpu/drm/vkms/vkms_output.c
>> +++ b/drivers/gpu/drm/vkms/vkms_output.c
>> @@ -31,13 +31,44 @@ static const struct drm_connector_funcs vkms_connector_funcs = {
>> .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>> };
>>
>> +static int vkms_connector_read_block(void *context, u8 *buf, unsigned int block, size_t len)
>> +{
>> + struct vkms_config_connector *config = context;
>> +
>> + if (block * len + len > config->edid_blob_len)
>
>The parameters to the read block function are a bit weird for historical
>reasons. The start offset is indicated by block number, length by
>len. The start byte offset is thus block * EDID_LENGTH! There's no
>smaller granularity for start offset. However len can be < EDID_LENGTH!
>
>So the above should be (block * EDID_LENGTH + len > edid_blob_len)
>
>> + return 1;
>> + memcpy(buf, &config->edid_blob[block * len], len);
>
>And this should be &config->edid_blob[block * EDID_LENGTH].
>
>(Your patch would work, but just by coincidence due to the way the read
>block function is currently called.)
Thanks for those clarifications!
>> + return 0;
>> +}
>> +
>> static int vkms_conn_get_modes(struct drm_connector *connector)
>> {
>> + const struct drm_edid *drm_edid = NULL;
>> int count;
>> + struct vkms_config_connector *connector_cfg;
>> + struct vkms_device *vkmsdev = drm_device_to_vkms_device(connector->dev);
>> + struct vkms_config_connector *context = NULL;
>> +
>> + list_for_each_entry(connector_cfg, &vkmsdev->config->connectors, link) {
>> + if (connector_cfg->connector == connector) {
>> + context = connector_cfg;
>> + break;
>> + }
>> + }
>> + if (context)
>> + drm_edid = drm_edid_read_custom(connector, vkms_connector_read_block, context);
>
>Thanks for using drm_edid_read_custom() for this btw!
>
>> +
>> + /*
>> + * Unconditionally update the connector. If the EDID was read
>> + * successfully, fill in the connector information derived from the
>> + * EDID. Otherwise, if the EDID is NULL, clear the connector
>> + * information.
>> + */
>> + drm_edid_connector_update(connector, drm_edid);
>> +
>> + count = drm_edid_connector_add_modes(connector);
>>
>> - /* Use the default modes list from DRM */
>> - count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
>> - drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
>
>I don't really know anything about your use case, but don't you want to
>fall back to the above for drm_edid == NULL? *shrug*
You are right, I will probably fallback to noedid version, at least for VIRTUAL connectors.
Or maybe I will add something in VKMS configuration to use "empty edid", "default modes_noedid" or "custom_edid".
This way you will be able to test all the scenarios for your userspace.
Thanks for your review,
Louis Chauvet
>BR,
>Jani.
>
>> + drm_edid_free(drm_edid);
>>
>> return count;
>> }
>
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