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 <[email protected]>
Intel Corporation,         
        

Initial version

Laurent Pinchart <[email protected]>
Ideas on board SPRL,         
        

Driver internals

Daniel Vetter <[email protected]>
Intel Corporation,         
        

Contributions all over the place

Lukas Wunner <[email protected]>

vga_switcheroo documentation

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