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drm/edid: abstract an EDID block read helper

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We have an abstraction for the EDID base block read, yet duplicating the
retries and error handling for extension block reads. Introduce a more
generic EDID block read helper.

Switch to the helper piecemeal, starting with drm_edid_get_panel_id(),
which doesn't need or have access to the connector anyway.

The subtle change is switching from drm_edid_block_valid() to
edid_block_check(). We also status print once, not for every attempt.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/47560f7530e4a7b32b56cb9038178244fe30a4af.1649685475.git.jani.nikula@intel.com
This commit is contained in:
Jani Nikula 2022-04-11 17:00:30 +03:00
parent 89fb7536ad
commit 2deaf1c256
1 changed files with 51 additions and 7 deletions
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58
drivers/gpu/drm/drm_edid.c
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@ -1670,6 +1670,7 @@ EXPORT_SYMBOL(drm_edid_are_equal);
enum edid_block_status {
EDID_BLOCK_OK = 0,
EDID_BLOCK_READ_FAIL,
EDID_BLOCK_NULL,
EDID_BLOCK_ZERO,
EDID_BLOCK_HEADER_CORRUPT,
@ -1736,6 +1737,9 @@ static void edid_block_status_print(enum edid_block_status status,
switch (status) {
case EDID_BLOCK_OK:
break;
case EDID_BLOCK_READ_FAIL:
pr_debug("EDID block %d read failed\n", block_num);
break;
case EDID_BLOCK_NULL:
pr_debug("EDID block %d pointer is NULL\n", block_num);
break;
@ -2039,6 +2043,39 @@ EXPORT_SYMBOL(drm_add_override_edid_modes);
typedef int read_block_fn(void *context, u8 *buf, unsigned int block, size_t len);
static enum edid_block_status edid_block_read(void *block, unsigned int block_num,
read_block_fn read_block,
void *context)
{
enum edid_block_status status;
bool is_base_block = block_num == 0;
int try;
for (try = 0; try < 4; try++) {
if (read_block(context, block, block_num, EDID_LENGTH))
return EDID_BLOCK_READ_FAIL;
status = edid_block_check(block, is_base_block);
if (status == EDID_BLOCK_HEADER_REPAIR) {
edid_header_fix(block);
/* Retry with fixed header, update status if that worked. */
status = edid_block_check(block, is_base_block);
if (status == EDID_BLOCK_OK)
status = EDID_BLOCK_HEADER_FIXED;
}
if (edid_block_status_valid(status, edid_block_tag(block)))
break;
/* Fail early for unrepairable base block all zeros. */
if (try == 0 && is_base_block && status == EDID_BLOCK_ZERO)
break;
}
return status;
}
static struct edid *drm_do_get_edid_base_block(struct drm_connector *connector,
read_block_fn read_block,
void *context)
@ -2237,20 +2274,27 @@ static u32 edid_extract_panel_id(const struct edid *edid)
u32 drm_edid_get_panel_id(struct i2c_adapter *adapter)
{
const struct edid *edid;
u32 panel_id;
edid = drm_do_get_edid_base_block(NULL, drm_do_probe_ddc_edid, adapter);
enum edid_block_status status;
void *base_block;
u32 panel_id = 0;
/*
* There are no manufacturer IDs of 0, so if there is a problem reading
* the EDID then we'll just return 0.
*/
if (!edid)
base_block = kmalloc(EDID_LENGTH, GFP_KERNEL);
if (!base_block)
return 0;
panel_id = edid_extract_panel_id(edid);
kfree(edid);
status = edid_block_read(base_block, 0, drm_do_probe_ddc_edid, adapter);
edid_block_status_print(status, base_block, 0);
if (edid_block_status_valid(status, edid_block_tag(base_block)))
panel_id = edid_extract_panel_id(base_block);
kfree(base_block);
return panel_id;
}