On Wed, 27 Apr 2016, Lyude cpaul@redhat.com wrote:
For MST encoders, the encoder struct is stored in the intel_dp_mst struct, not a intel_digital_port struct.
This fixes issues with hotplugging MST displays that support MST audio, where hotplugging had a surprisingly good chance of accidentally overwriting other parts of the kernel leading to seemingly unrelated backtraces in sysfs, ext4, etc.
Cc: stable@vger.kernel.org Signed-off-by: Lyude cpaul@redhat.com
Ugh. Just ugh.
At a glance, it's probably this one that starts calling intel_audio_codec_enable() and intel_audio_codec_disable() on DP MST:
commit 3d52ccf52f2c51f613e42e65be0f06e4e6788093 Author: Libin Yang libin.yang@linux.intel.com Date: Wed Dec 2 14:09:44 2015 +0800
drm/i915: start adding dp mst audio
which has been there since v4.5. Would it be feasible for you to revert the commit or change it so that it stops calling the audio codec enable/disable, to verify this is the culprit? So we could add a proper Fixes: line too.
The non-MST aware enc_to_dig_port() calls on platforms that might have MST were added in:
commit 51e1d83cab9988716ae68801a721f4df0aaa374b Author: David Henningsson david.henningsson@canonical.com Date: Wed Aug 19 10:48:56 2015 +0200
drm/i915: Call audio pin/ELD notify function
and:
commit 7e8275c2f2bbb384e18af37066b8b2f32b7d092f Author: Libin Yang libin.yang@intel.com Date: Fri Sep 25 09:36:12 2015 +0800
drm/i915: set proper N/CTS in modeset
but I don't think the codec enable/disable were called on MST at that time.
Some of the problem was probably seen by Takashi in
commit 0bdf5a05647a66dcc6394986e061daeac9b1cf96 Author: Takashi Iwai tiwai@suse.de Date: Mon Nov 30 18:19:39 2015 +0100
drm/i915: Add reverse mapping between port and intel_encoder
which has a comment /* intel_encoder might be NULL for DP MST */. Maybe that needs to be updated to DTRT too.
Lyude, thanks for your efforts in DP MST area. Much appreciated.
BR, Jani.
drivers/gpu/drm/i915/intel_drv.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 4c027d6..81f2212 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -918,18 +918,23 @@ intel_attached_encoder(struct drm_connector *connector) return to_intel_connector(connector)->encoder; }
-static inline struct intel_digital_port * -enc_to_dig_port(struct drm_encoder *encoder) -{
- return container_of(encoder, struct intel_digital_port, base.base);
-}
static inline struct intel_dp_mst_encoder * enc_to_mst(struct drm_encoder *encoder) { return container_of(encoder, struct intel_dp_mst_encoder, base.base); }
+static inline struct intel_digital_port * +enc_to_dig_port(struct drm_encoder *encoder) +{
- if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST)
return enc_to_mst(encoder)->primary;- else {
return container_of(encoder, struct intel_digital_port,base.base);- }
+}
static inline struct intel_dp *enc_to_intel_dp(struct drm_encoder *encoder) { return &enc_to_dig_port(encoder)->dp;