This patch adds support in probing 4 block edid data, for E-DDC. This is the first test case in CTS, for HDMI compliance.
Changes from V4: Fix review comments about space and comment indentation.
Based on drm-next branch
Shirish S (1): drm: edid: add support for E-DDC
drivers/gpu/drm/drm_edid.c | 22 +++++++++++++++++++--- 1 files changed, 19 insertions(+), 3 deletions(-)
The current logic for probing ddc is limited to 2 blocks (256 bytes), this patch adds support for the 4 block (512) data.
To do this, a single 8-bit segment index is passed to the display via the I2C address 30h. Data from the selected segment is then immediately read via the regular DDC2 address using a repeated I2C 'START' signal.
Signed-off-by: Shirish S s.shirish@samsung.com --- drivers/gpu/drm/drm_edid.c | 22 +++++++++++++++++++--- 1 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index bcc4725..b9ffc30 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -254,6 +254,8 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, int block, int len) { unsigned char start = block * EDID_LENGTH; + unsigned char segment = block >> 1; + unsigned char xfers = segment ? 3 : 2; int ret, retries = 5;
/* The core i2c driver will automatically retry the transfer if the @@ -265,6 +267,11 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, do { struct i2c_msg msgs[] = { { + .addr = DDC_SEGMENT_ADDR, + .flags = segment ? 0 : I2C_M_IGNORE_NAK, + .len = 1, + .buf = &segment, + }, { .addr = DDC_ADDR, .flags = 0, .len = 1, @@ -276,15 +283,24 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf, .buf = buf, } }; - ret = i2c_transfer(adapter, msgs, 2); + + /* + * Avoid sending the segment addr to not upset non-compliant ddc + * monitors. + */ + if (!segment) + ret = i2c_transfer(adapter, &msgs[1], xfers); + else + ret = i2c_transfer(adapter, msgs, xfers); + if (ret == -ENXIO) { DRM_DEBUG_KMS("drm: skipping non-existent adapter %s\n", adapter->name); break; } - } while (ret != 2 && --retries); + } while (ret != xfers && --retries);
- return ret == 2 ? 0 : -1; + return ret == xfers ? 0 : -1; }
static bool drm_edid_is_zero(u8 *in_edid, int length)
On Wed, Aug 29, 2012 at 4:46 PM, Shirish S s.shirish@samsung.com wrote:
If you resend patches it'd be nice to keep a changelog of the patch itself somewhere, otherwise it's just more work to figure that out for reviewers. Also, you can usually attach reviewed-by tags (like mine) to a patch resend if you don't change the patch massively ... -Daniel
Thanks for the comments Daniel and Jean I will upload patch set 6. This shall include Jean's review coments. And i will tag Daniel,Jean and Ville as reviewed.
Regards, Shirish S
On Wed, Aug 29, 2012 at 9:12 AM, Daniel Vetter daniel@ffwll.ch wrote:
dri-devel@lists.freedesktop.org
-
Daniel Vetter -
Shirish S -
Shirish S