diff options
| -rw-r--r-- | sys/dev/drm2/drm_edid.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/sys/dev/drm2/drm_edid.c b/sys/dev/drm2/drm_edid.c index 827677d..86306b9 100644 --- a/sys/dev/drm2/drm_edid.c +++ b/sys/dev/drm2/drm_edid.c @@ -253,6 +253,8 @@ drm_do_probe_ddc_edid(device_t 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 @@ -264,6 +266,11 @@ drm_do_probe_ddc_edid(device_t adapter, unsigned char *buf, do { struct iic_msg msgs[] = { { + .slave = DDC_SEGMENT_ADDR << 1, + .flags = 0, + .len = 1, + .buf = &segment, + }, { .slave = DDC_ADDR << 1, .flags = IIC_M_WR, .len = 1, @@ -275,7 +282,13 @@ drm_do_probe_ddc_edid(device_t adapter, unsigned char *buf, .buf = buf, } }; - ret = iicbus_transfer(adapter, msgs, 2); + + /* + * Avoid sending the segment addr to not upset non-compliant ddc + * monitors. + */ + ret = iicbus_transfer(adapter, &msgs[3 - xfers], xfers); + if (ret != 0) DRM_DEBUG_KMS("iicbus_transfer countdown %d error %d\n", retries, ret); |
