The driver was originally added in commit fcfa0ddc18ed ("drm/bridge:
Drivers for megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)"). I tried to
look up the discussion, but didn't find anyone questioning the EDID
reading part.
Why does it not use drm_get_edid() or drm_do_get_edid()?
I don't know where client->addr comes from, so I guess it could be
different from DDC_ADDR, rendering drm_get_edid() unusable.
There's also the comment:
/* Yes, read the entire buffer, and do not skip the first
* EDID_LENGTH bytes.
*/
But again, there's not a word on *why*.
Maybe we could just use drm_do_get_edid()? I'd like drivers to migrate
away from their own EDID parsing and validity checks, including stop
using drm_edid_block_valid(). (And long term switch to drm_edid_read(),
struct drm_edid, and friends, but this is the first step.)
Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
Cc: Ian Ray <ian.ray@xxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Martin Donnelly <martin.donnelly@xxxxxx>
Cc: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>
Cc: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Cc: Peter Senna Tschudin <peter.senna@xxxxxxxxx>
Cc: Robert Foss <rfoss@xxxxxxxxxx>
Cc: Yuan Can <yuancan@xxxxxxxxxx>
Cc: Zheyu Ma <zheyuma97@xxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
I haven't even tried to compile this, and I have no way to test
this. Apologies for the long Cc list; I'm hoping someone could explain
the existing code, and perhaps give this approach a spin.
---
.../bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 57 +++----------------
1 file changed, 9 insertions(+), 48 deletions(-)
diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
index 460db3c8a08c..0d9eacf3d9b7 100644
--- a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
+++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
@@ -65,12 +65,11 @@ struct ge_b850v3_lvds {
static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
-static u8 *stdp2690_get_edid(struct i2c_client *client)
+static int stdp2690_read_block(void *context, u8 *buf, unsigned int block, size_t len)
{
+ struct i2c_client *client = context;
struct i2c_adapter *adapter = client->adapter;
- unsigned char start = 0x00;
- unsigned int total_size;
- u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
+ unsigned char start = block * EDID_LENGTH;
struct i2c_msg msgs[] = {
{
@@ -81,53 +80,15 @@ static u8 *stdp2690_get_edid(struct i2c_client *client)
}, {
.addr = client->addr,
.flags = I2C_M_RD,
- .len = EDID_LENGTH,
- .buf = block,
+ .len = len,
+ .buf = buf,
}
};
- if (!block)
- return NULL;
+ if (i2c_transfer(adapter, msgs, 2) != 2)
+ return -1;
- if (i2c_transfer(adapter, msgs, 2) != 2) {
- DRM_ERROR("Unable to read EDID.\n");
- goto err;
- }
-
- if (!drm_edid_block_valid(block, 0, false, NULL)) {
- DRM_ERROR("Invalid EDID data\n");
- goto err;
- }
-
- total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
- if (total_size > EDID_LENGTH) {
- kfree(block);
- block = kmalloc(total_size, GFP_KERNEL);
- if (!block)
- return NULL;
-
- /* Yes, read the entire buffer, and do not skip the first
- * EDID_LENGTH bytes.
- */
- start = 0x00;
- msgs[1].len = total_size;
- msgs[1].buf = block;
-
- if (i2c_transfer(adapter, msgs, 2) != 2) {
- DRM_ERROR("Unable to read EDID extension blocks.\n");
- goto err;
- }
- if (!drm_edid_block_valid(block, 1, false, NULL)) {
- DRM_ERROR("Invalid EDID data\n");
- goto err;
- }
- }
-
- return block;
-
-err:
- kfree(block);
- return NULL;
+ return 0;
}
static struct edid *ge_b850v3_lvds_get_edid(struct drm_bridge *bridge,
@@ -137,7 +98,7 @@ static struct edid *ge_b850v3_lvds_get_edid(struct drm_bridge *bridge,
client = ge_b850v3_lvds_ptr->stdp2690_i2c;
- return (struct edid *)stdp2690_get_edid(client);
+ return drm_do_get_edid(connector, stdp2690_read_block, client, NULL);
}
static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
--
2.39.2
