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
(cherry picked from commit f58a1acc7e)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Daniel Vetter 2016-05-03 10:33:01 +02:00 committed by Jani Nikula
parent 26792526cc
commit 2700818ac9
1 changed files with 7 additions and 1 deletions

View File

@ -257,8 +257,14 @@ static bool intel_crt_compute_config(struct intel_encoder *encoder,
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)) {