Re: [PATCH 1/2] drm/i915/dp: Print full branch/sink descriptor for all outputs

Jani Nikula
2016-10-20T18:07:04Z

On Thu, 20 Oct 2016, Imre Deak <imre.deak@intel.com> wrote:
> Extend the branch/sink descriptor info with the missing device ID
> field and print this info for eDP and LSPCON connectors too.
>
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 83 +++++++++++++++----------------------
> drivers/gpu/drm/i915/intel_drv.h | 13 ++++++
> drivers/gpu/drm/i915/intel_lspcon.c | 7 ++++
> 3 files changed, 53 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 88f3b74..e90211e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1442,42 +1442,34 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
> DRM_DEBUG_KMS("common rates: %s\n", str);
> }
>
> -static void intel_dp_print_hw_revision(struct intel_dp *intel_dp)
> +static bool intel_dp_is_branch(struct intel_dp *intel_dp)

Belongs in drm dp helpers.

> {
> - uint8_t rev;
> - int len;
> -
> - if ((drm_debug & DRM_UT_KMS) == 0)
> - return;
> -
> - if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> - DP_DWN_STRM_PORT_PRESENT))
> - return;
> -
> - len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_HW_REV, &rev, 1);
> - if (len < 0)
> - return;
> -
> - DRM_DEBUG_KMS("sink hw revision: %d.%d\n", (rev & 0xf0) >> 4, rev & 0xf);
> + return intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> + DP_DWN_STRM_PORT_PRESENT;
> }
>
> -static void intel_dp_print_sw_revision(struct intel_dp *intel_dp)
> +bool
> +intel_dp_read_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc)
> {
> - uint8_t rev[2];
> - int len;
> + u32 base = intel_dp_is_branch(intel_dp) ? DP_BRANCH_OUI : DP_SINK_OUI;
>
> - if ((drm_debug & DRM_UT_KMS) == 0)
> - return;
> + return drm_dp_dpcd_read(&intel_dp->aux, base, desc, sizeof(*desc)) ==
> + sizeof(*desc);

Starting to read either branch or sink oui should be a standalone prep
change. I guess this should be done, although I've seen crappy devices
that report oui in wrong place...

> +}
>
> - if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> - DP_DWN_STRM_PORT_PRESENT))
> - return;
> +void
> +intel_dp_print_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc)
> +{
> + const char *dev_type = intel_dp_is_branch(intel_dp) ? "branch" : "sink";
> + bool oui_sup = intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] &
> + DP_OUI_SUPPORT;
>
> - len = drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_SW_REV, &rev, 2);
> - if (len < 0)
> - return;
> -
> - DRM_DEBUG_KMS("sink sw revision: %d.%d\n", rev[0], rev[1]);
> + DRM_DEBUG_KMS("DP %s: OUI %*phD%s dev-ID %.*s HW-rev %d.%d SW-rev %d.%d\n",
> + dev_type,
> + (int)sizeof(desc->oui), desc->oui, oui_sup ? "" : "(NS)",
> + (int)sizeof(desc->device_id), desc->device_id,
> + (desc->hw_rev & 0xf0) >> 4, (desc->hw_rev & 0xf),
> + desc->sw_major_rev, desc->sw_minor_rev);

I've been thinking about starting to print this stuff too. But again,
could be a standalone change.

> }
>
> static int rate_to_index(int find, const int *rates)
> @@ -3519,6 +3511,13 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
> if (!intel_dp_read_dpcd(intel_dp))
> return false;
>
> + if (drm_debug & DRM_UT_KMS) {
> + struct intel_dp_desc desc;
> +
> + if (intel_dp_read_desc(intel_dp, &desc))
> + intel_dp_print_desc(intel_dp, &desc);
> + }

I *really* don't think we should do dpcd access conditional to drm
debugs. I smell heisenbugs just thinking about it.

> +
> if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11)
> dev_priv->no_aux_handshake = intel_dp->dpcd[DP_MAX_DOWNSPREAD] &
> DP_NO_AUX_HANDSHAKE_LINK_TRAINING;
> @@ -3621,23 +3620,6 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> return true;
> }
>
> -static void
> -intel_dp_probe_oui(struct intel_dp *intel_dp)
> -{
> - u8 buf[3];
> -
> - if (!(intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
> - return;
> -
> - if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_OUI, buf, 3) == 3)
> - DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n",
> - buf[0], buf[1], buf[2]);
> -
> - if (drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_OUI, buf, 3) == 3)
> - DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
> - buf[0], buf[1], buf[2]);
> -}
> -
> static bool
> intel_dp_can_mst(struct intel_dp *intel_dp)
> {
> @@ -4410,11 +4392,12 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
> yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
>
> intel_dp_print_rates(intel_dp);
> + if (drm_debug & DRM_UT_KMS) {
> + struct intel_dp_desc desc;
>
> - intel_dp_probe_oui(intel_dp);
> -
> - intel_dp_print_hw_revision(intel_dp);
> - intel_dp_print_sw_revision(intel_dp);
> + if (intel_dp_read_desc(intel_dp, &desc))
> + intel_dp_print_desc(intel_dp, &desc);
> + }

Ditto. I do like putting the desc reading into one place though.

>
> intel_dp_configure_mst(intel_dp);
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index c06a33e..a35e241 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -883,6 +883,14 @@ enum link_m_n_set {
> M2_N2
> };
>
> +struct intel_dp_desc {
> + u8 oui[3];
> + u8 device_id[6];
> + u8 hw_rev;
> + u8 sw_major_rev;
> + u8 sw_minor_rev;
> +} __packed;
> +

I understand this, but makes me wonder about dp helpers vs. i915. I
guess we could add this for now.

> struct intel_dp {
> i915_reg_t output_reg;
> i915_reg_t aux_ch_ctl_reg;
> @@ -1460,6 +1468,11 @@ static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
> return ~((1 << lane_count) - 1) & 0xf;
> }
>
> +bool
> +intel_dp_read_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc);
> +void
> +intel_dp_print_desc(struct intel_dp *intel_dp, struct intel_dp_desc *desc);
> +
> /* intel_dp_aux_backlight.c */
> int intel_dp_aux_init_backlight_funcs(struct intel_connector *intel_connector);
>
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index 632149c..d2c8cb2 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -131,6 +131,13 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
> }
> }
>
> + if (drm_debug & DRM_UT_KMS) {
> + struct intel_dp_desc desc;
> +
> + if (intel_dp_read_desc(dp, &desc))
> + intel_dp_print_desc(dp, &desc);
> + }

Again, reads conditional to debugs is scary.

> +
> DRM_DEBUG_KMS("Success: LSPCON init\n");
> return true;
> }

--
Jani Nikula, Intel Open Source Technology Center