On Wed, 12 Aug 2015, Thierry Reding thierry.reding@gmail.com wrote:
From: Thierry Reding treding@nvidia.com
If the sink support eDP, read the eDP revision from it's DPCD.
Signed-off-by: Thierry Reding treding@nvidia.com
drivers/gpu/drm/drm_dp_helper.c | 30 +++++++++++++++++++++++++++++- include/drm/drm_dp_helper.h | 1 + 2 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 1fe181525604..c711b690508b 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -295,7 +295,7 @@ EXPORT_SYMBOL(drm_dp_dpcd_read_link_status); */ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) {
- u8 values[7];
u8 values[16], value; int err;
memset(link, 0, sizeof(*link));
@@ -323,6 +323,34 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) if (values[6] & DP_SET_ANSI_8B10B) link->capabilities |= DP_LINK_CAP_ANSI_8B10B;
- if (values[13] & DP_ALTERNATE_SCRAMBLER_RESET_CAP) {
That's not indicative of eDP, that's indicative of edp && alternate scrambler support. DPCD_DISPLAY_CONTROL_CAPABLE bit is a better match:
"To allow Source devices to easily identify panels that use DPCD Addresses 00700h through 007FFh, the DPCD_DISPLAY_CONTROL_CAPABLE bit in the eDP_CONFIGURATION_CAP register (DPCD Address 0000Dh, bit 3) has been assigned (eDP v1.2 (and higher)) to indicate this capability, as described in Table 3-3."
Also, I'd really appreciate using the macros for DPCD offsets. I do not remember these offsets by heart, and we've defined the macros according to the spec so it would be faster to look things up there.
err = drm_dp_dpcd_readb(aux, DP_EDP_DPCD_REV, &value);if (err < 0)return err;switch (value) {case DP_EDP_11:link->edp = 0x11;
I'm really not sure if this is a good idea, since DP_EDP_11 == 0. Essentially you're promoting to use the magic values for the version checking in code. Sure, we've done that with the DPCD version, but now link->revision is directly from DPCD, and this would not be.
BR, Jani.
break;case DP_EDP_12:link->edp = 0x12;break;case DP_EDP_13:link->edp = 0x13;break;case DP_EDP_14:link->edp = 0x14;break;default:DRM_ERROR("unsupported eDP version: %02x\n", value);break;}- }
- return 0;
} EXPORT_SYMBOL(drm_dp_link_probe); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 9e70ea8b907d..f9e7f484a225 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -749,6 +749,7 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
struct drm_dp_link { unsigned char revision;
- unsigned char edp; unsigned int rate; unsigned int num_lanes; unsigned long capabilities;
-- 2.4.5
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