On Tue, Aug 11, 2020 at 04:04:53PM -0400, Lyude Paul wrote:
> And of course, we'll also need to read the sink count from other drivers
> as well if we're checking whether or not it's supported. So, let's
> extract the code for this into another helper.
>
> Signed-off-by: Lyude Paul <ly...@redhat.com>
> ---
> drivers/gpu/drm/drm_dp_helper.c | 20 ++++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++------------
> include/drm/drm_dp_helper.h | 1 +
> 3 files changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 05bb47e589731..0ff2959c8f8e8 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -722,6 +722,26 @@ bool drm_dp_has_sink_count(struct drm_connector
> *connector,
> }
> EXPORT_SYMBOL(drm_dp_has_sink_count);
>
> +/**
> + * drm_dp_get_sink_count() - Retrieve the sink count for a given sink
> + * @aux: The DP AUX channel to use
> + *
> + * Returns: The current sink count reported by @aux, or a negative error code
> + * otherwise.
> + */
> +int drm_dp_get_sink_count(struct drm_dp_aux *aux)
> +{
> + u8 count;
> + int ret;
> +
> + ret = drm_dp_dpcd_readb(aux, DP_SINK_COUNT, &count);
> + if (ret < 1)
> + return -EIO;
This should probably be:
if (ret < 0)
return ret;
else if (ret != 1)
return -EIO;
> +
> + return DP_GET_SINK_COUNT(count);
> +}
> +EXPORT_SYMBOL(drm_dp_get_sink_count);
> +
> /*
> * I2C-over-AUX implementation
> */
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 35a4779a442e2..e343965a483df 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4648,6 +4648,8 @@ intel_dp_has_sink_count(struct intel_dp *intel_dp)
> static bool
> intel_dp_get_dpcd(struct intel_dp *intel_dp)
> {
> + int ret;
> +
> if (!intel_dp_read_dpcd(intel_dp))
> return false;
>
> @@ -4664,20 +4666,10 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> }
>
> if (intel_dp_has_sink_count(intel_dp)) {
> - u8 count;
> - ssize_t r;
> -
> - r = drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT, &count);
> - if (r < 1)
> + ret = drm_dp_get_sink_count(&intel_dp->aux);
> + if (ret < 0)
> return false;
>
> - /*
> - * Sink count can change between short pulse hpd hence
> - * a member variable in intel_dp will track any changes
> - * between short pulse interrupts.
> - */
I think you could probably keep this comment and relocate the
intel_dp->sink_count
assignment back.
With these nits (or something like them),
Reviewed-by: Sean Paul <s...@poorly.run>
> - intel_dp->sink_count = DP_GET_SINK_COUNT(count);
> -
> /*
> * SINK_COUNT == 0 and DOWNSTREAM_PORT_PRESENT == 1 implies that
> * a dongle is present but no display. Unless we require to know
> @@ -4685,6 +4677,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> * downstream port information. So, an early return here saves
> * time from performing other operations which are not required.
> */
> + intel_dp->sink_count = ret;
> if (!intel_dp->sink_count)
> return false;
> }
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index a1413a531eaf4..0c141fc81aaa8 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1635,6 +1635,7 @@ struct drm_dp_desc;
> bool drm_dp_has_sink_count(struct drm_connector *connector,
> const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> const struct drm_dp_desc *desc);
> +int drm_dp_get_sink_count(struct drm_dp_aux *aux);
>
> void drm_dp_remote_aux_init(struct drm_dp_aux *aux);
> void drm_dp_aux_init(struct drm_dp_aux *aux);
> --
> 2.26.2
>
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--
Sean Paul, Software Engineer, Google / Chromium OS
