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DRM_DP_DPCD_READ(9) DRM Core DRM_DP_DPCD_READ(9)

NAME

drm_dp_dpcd_read - read a series of bytes from the DPCD

SYNOPSIS

ssize_t drm_dp_dpcd_read(struct drm_dp_aux * aux, unsigned int offset, void * buffer, size_t size);

ARGUMENTS

aux
DisplayPort AUX channel
offset
address of the (first) register to read
buffer
buffer to store the register values
size
number of bytes in buffer

DESCRIPTION

Returns the number of bytes transferred on success, or a negative error code on failure. -EIO is returned if the request was NAKed by the sink or if the retry count was exceeded. If not all bytes were transferred, this function returns -EPROTO. Errors from the underlying AUX channel transfer function, with the exception of -EBUSY (which causes the transaction to be retried), are propagated to the caller.

AUTHORS

Jesse Barnes <jesse.barnes@intel.com>
 
Intel Corporation,
Initial version
Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 
Ideas on board SPRL,
Driver internals
Daniel Vetter <daniel.vetter@ffwll.ch>
 
Intel Corporation,
Contributions all over the place

COPYRIGHT

May 2018 Kernel Hackers Manual 3.16