BugLink: http://bugs.launchpad.net/bugs/1195483 This reverts commit 657445fe8660100ad174600ebfa61536392b7624. Signed-off-by: Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Paulo Zanoni <przanoni@xxxxxxxxx> Cc: David Airlie <airlied@xxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/gpu/drm/i915/intel_dp.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 26e162b..ce933ad 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -709,10 +709,7 @@ intel_dp_compute_config(struct intel_encoder *encoder, /* Walk through all bpp values. Luckily they're all nicely spaced with 2 * bpc in between. */ - bpp = pipe_config->pipe_bpp; - if (is_edp(intel_dp) && dev_priv->vbt.edp_bpp) - bpp = min_t(int, bpp, dev_priv->vbt.edp_bpp); - + bpp = min_t(int, 8*3, pipe_config->pipe_bpp); for (; bpp >= 6*3; bpp -= 2*3) { mode_rate = intel_dp_link_required(adjusted_mode->clock, bpp); @@ -763,6 +760,19 @@ found: &pipe_config->dp_m_n); intel_dp_set_clock(encoder, pipe_config, intel_dp->link_bw); + /* + * XXX: We have a strange regression where using the vbt edp bpp value + * for the link bw computation results in black screens, the panel only + * works when we do the computation at the usual 24bpp (but still + * requires us to use 18bpp). Until that's fully debugged, stay + * bug-for-bug compatible with the old code. + */ + if (is_edp(intel_dp) && dev_priv->vbt.edp_bpp) { + DRM_DEBUG_KMS("clamping display bpc (was %d) to eDP (%d)\n", + bpp, dev_priv->vbt.edp_bpp); + bpp = min_t(int, bpp, dev_priv->vbt.edp_bpp); + } + pipe_config->pipe_bpp = bpp; return true; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html