On Fri, Apr 4, 2014 at 2:09 AM, Jani Nikula jani.nikula@linux.intel.com wrote:
On Sat, 22 Mar 2014, Alex Deucher alexdeucher@gmail.com wrote:
This adds a flags field and a new flag, BARE_ADDRESS, which drivers can use for special handling when they want to set just the aux address. This is needed to properly reset the connection between i2c transactions.
Sorry it took me so long to get to this.
The changes in patches 1-3 look sensible in general, but I think I'd prefer you dropped the flags field and used size == 0 to mean bare address. It feels silly to have to set size = 1 and have a dummy one byte buffer that doesn't get transfered. Without the payload I think it feels natural only the address is transfered.
Thanks. I'll resend with size = 0. Note that it doesn't look like the current intel dp code handles zero sized transfers so that will need to be fixed up.
Alex
BR, Jani.
Signed-off-by: Alex Deucher alexander.deucher@amd.com
include/drm/drm_dp_helper.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index b7488c9..a006e96 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -403,6 +403,8 @@ drm_dp_enhanced_frame_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
- DisplayPort AUX channel
*/
+#define DRM_DP_AUX_MSG_FLAGS_BARE_ADDRESS (1 << 0)
/**
- struct drm_dp_aux_msg - DisplayPort AUX channel transaction
- @address: address of the (first) register to access
@@ -417,6 +419,7 @@ struct drm_dp_aux_msg { u8 reply; void *buffer; size_t size;
u32 flags;};
/**
1.8.3.1
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-- Jani Nikula, Intel Open Source Technology Center