[PATCH v4 02/15] drm/edid: Break out reading block 0 of the EDID

From: Douglas Anderson
Date: Thu Sep 09 2021 - 17:01:41 EST


A future change wants to be able to read just block 0 of the EDID, so
break it out of drm_do_get_edid() into a sub-function.

This is intended to be a no-op change--just code movement.

Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
---

Changes in v4:
- "u8 *edid" => "void *edid" to avoid cast.
- Don't put kmalloc() in the "if" test even if the old code did.
- drm_do_get_edid_blk0() => drm_do_get_edid_base_block()

drivers/gpu/drm/drm_edid.c | 63 +++++++++++++++++++++++++++-----------
1 file changed, 45 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 6325877c5fd6..520fe1391769 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1905,6 +1905,44 @@ int drm_add_override_edid_modes(struct drm_connector *connector)
}
EXPORT_SYMBOL(drm_add_override_edid_modes);

+static struct edid *drm_do_get_edid_base_block(
+ int (*get_edid_block)(void *data, u8 *buf, unsigned int block,
+ size_t len),
+ void *data, bool *edid_corrupt, int *null_edid_counter)
+{
+ int i;
+ void *edid;
+
+ edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
+ if (edid == NULL)
+ return NULL;
+
+ /* base block fetch */
+ for (i = 0; i < 4; i++) {
+ if (get_edid_block(data, edid, 0, EDID_LENGTH))
+ goto out;
+ if (drm_edid_block_valid(edid, 0, false, edid_corrupt))
+ break;
+ if (i == 0 && drm_edid_is_zero(edid, EDID_LENGTH)) {
+ if (null_edid_counter)
+ (*null_edid_counter)++;
+ goto carp;
+ }
+ }
+ if (i == 4)
+ goto carp;
+
+ return edid;
+
+carp:
+ kfree(edid);
+ return ERR_PTR(-EINVAL);
+
+out:
+ kfree(edid);
+ return NULL;
+}
+
/**
* drm_do_get_edid - get EDID data using a custom EDID block read function
* @connector: connector we're probing
@@ -1938,25 +1976,16 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
if (override)
return override;

- if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
+ edid = (u8 *)drm_do_get_edid_base_block(get_edid_block, data,
+ &connector->edid_corrupt,
+ &connector->null_edid_counter);
+ if (IS_ERR_OR_NULL(edid)) {
+ if (IS_ERR(edid))
+ connector_bad_edid(connector, edid, 1);
return NULL;
-
- /* base block fetch */
- for (i = 0; i < 4; i++) {
- if (get_edid_block(data, edid, 0, EDID_LENGTH))
- goto out;
- if (drm_edid_block_valid(edid, 0, false,
- &connector->edid_corrupt))
- break;
- if (i == 0 && drm_edid_is_zero(edid, EDID_LENGTH)) {
- connector->null_edid_counter++;
- goto carp;
- }
}
- if (i == 4)
- goto carp;

- /* if there's no extensions, we're done */
+ /* if there's no extensions or no connector, we're done */
valid_extensions = edid[0x7e];
if (valid_extensions == 0)
return (struct edid *)edid;
@@ -2010,8 +2039,6 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,

return (struct edid *)edid;

-carp:
- connector_bad_edid(connector, edid, 1);
out:
kfree(edid);
return NULL;
--
2.33.0.309.g3052b89438-goog