From b31e85eda38c58cae986162ae2c462b53b0a2065 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Thu, 18 May 2017 14:10:25 +0300 Subject: drm/i915: Detect USB-C specific dongles before reducing M and N MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The Analogix 7737 DP to HDMI converter requires reduced M and N values when to operate correctly at HBR2. We tried to reduce the M/N values for all devices in commit 9a86cda07af2 ("drm/i915/dp: reduce link M/N parameters"), but that regressed some other sinks. Detect this IC by its OUI value of 0x0022B9 via the DPCD quirk list, and only reduce the M/N values for that. v2 by Jani: Rebased on the DP quirk database v3 by Jani: Rebased on the reworked DP quirk database v4 by Jani: Improve commit message (Daniel) Fixes: 9a86cda07af2 ("drm/i915/dp: reduce link M/N parameters") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93578 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100755 Cc: Jani Nikula Cc: Dhinakaran Pandiyan Cc: Ville Syrjälä Reviewed-by: Daniel Vetter Signed-off-by: Clint Taylor Signed-off-by: Jani Nikula Link: http://patchwork.freedesktop.org/patch/msgid/2d2e30f8f47d3f28c9b74ca2612336a54585c3ec.1495105635.git.jani.nikula@intel.com --- drivers/gpu/drm/i915/intel_dp_mst.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/intel_dp_mst.c') diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c index c1f62eb07c07..989e25577ac0 100644 --- a/drivers/gpu/drm/i915/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/intel_dp_mst.c @@ -44,6 +44,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, int lane_count, slots; const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode; int mst_pbn; + bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc, + DP_DPCD_QUIRK_LIMITED_M_N); pipe_config->has_pch_encoder = false; bpp = 24; @@ -75,7 +77,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder, intel_link_compute_m_n(bpp, lane_count, adjusted_mode->crtc_clock, pipe_config->port_clock, - &pipe_config->dp_m_n); + &pipe_config->dp_m_n, + reduce_m_n); pipe_config->dp_m_n.tu = slots; -- cgit