drm/i915: Bail out of pipe config compute loop on LPT
LPT is pch, so might run into the fdi bandwidth constraint (especially
since it has only 2 lanes). But right now we just force pipe_bpp back
to 24, resulting in a nice loop (which we bail out with a loud
WARN_ON). Fix this.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=93477
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1462264381-7573-1-git-send-email-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index a2a31fd..3fbb6fc 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -261,8 +261,14 @@
pipe_config->has_pch_encoder = true;
/* LPT FDI RX only supports 8bpc. */
- if (HAS_PCH_LPT(dev))
+ if (HAS_PCH_LPT(dev)) {
+ if (pipe_config->bw_constrained && pipe_config->pipe_bpp < 24) {
+ DRM_DEBUG_KMS("LPT only supports 24bpp\n");
+ return false;
+ }
+
pipe_config->pipe_bpp = 24;
+ }
/* FDI must always be 2.7 GHz */
if (HAS_DDI(dev))