From f12110afee058a2e6e816e315d3291765625cc87 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Fri, 4 Dec 2020 17:35:55 -0500 Subject: [PATCH] drm/i915/dp: Program source OUI on eDP panels Since we're about to start adding support for Intel's magic HDR backlight interface over DPCD, we need to ensure we're properly programming this field so that Intel specific sink services are exposed. Otherwise, 0x300-0x3ff will just read zeroes. We also take care not to reprogram the source OUI if it already matches what we expect. This is just to be careful so that we don't accidentally take the panel out of any backlight control modes we found it in. v2: * Add careful parameter to intel_edp_init_source_oui() to avoid re-writing the source OUI if it's already been set during driver initialization Signed-off-by: Lyude Paul Reviewed-by: Rodrigo Vivi Cc: thaytan@noraisin.net Cc: Vasily Khoruzhick Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20201204223603.249878-2-lyude@redhat.com --- drivers/gpu/drm/i915/display/intel_dp.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index b2bc0c8..02d9279 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -3591,6 +3591,29 @@ void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp, enable ? "enable" : "disable"); } +static void +intel_edp_init_source_oui(struct intel_dp *intel_dp, bool careful) +{ + struct drm_i915_private *i915 = dp_to_i915(intel_dp); + u8 oui[] = { 0x00, 0xaa, 0x01 }; + u8 buf[3] = { 0 }; + + /* + * During driver init, we want to be careful and avoid changing the source OUI if it's + * already set to what we want, so as to avoid clearing any state by accident + */ + if (careful) { + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SOURCE_OUI, buf, sizeof(buf)) < 0) + drm_err(&i915->drm, "Failed to read source OUI\n"); + + if (memcmp(oui, buf, sizeof(oui)) == 0) + return; + } + + if (drm_dp_dpcd_write(&intel_dp->aux, DP_SOURCE_OUI, oui, sizeof(oui)) < 0) + drm_err(&i915->drm, "Failed to write source OUI\n"); +} + /* If the device supports it, try to set the power state appropriately */ void intel_dp_set_power(struct intel_dp *intel_dp, u8 mode) { @@ -3612,6 +3635,10 @@ void intel_dp_set_power(struct intel_dp *intel_dp, u8 mode) lspcon_resume(dp_to_dig_port(intel_dp)); + /* Write the source OUI as early as possible */ + if (intel_dp_is_edp(intel_dp)) + intel_edp_init_source_oui(intel_dp, false); + /* * When turning on, we need to retry for 1ms to give the sink * time to wake up. @@ -4877,6 +4904,12 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp) if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv)) intel_dp_get_dsc_sink_cap(intel_dp); + /* + * If needed, program our source OUI so we can make various Intel-specific AUX services + * available (such as HDR backlight controls) + */ + intel_edp_init_source_oui(intel_dp, true); + return true; } -- 2.7.4