On Wed, 2017-06-21 at 12:59 +0200, Maarten Lankhorst wrote:
> When reading all debugfs files on a system with DP-MST the kernel panics
> on a null pointer dereference because intel_dp is null for a DP-MST
> connector. Detect this case and skip those connectors.
>
> Signed-off-by: Maarten Lankhorst <[email protected]>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 33 ++++++++++++++++++++++++---------
> 1 file changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c
> b/drivers/gpu/drm/i915/i915_debugfs.c
> index 1f1176b6400e..30e2e168fe92 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
I think you missed i915_displayport_test_active_write(). Looks good
otherwise.
-DK
> @@ -3812,13 +3812,18 @@ static int i915_displayport_test_active_show(struct
> seq_file *m, void *data)
>
> drm_connector_list_iter_begin(dev, &conn_iter);
> drm_for_each_connector_iter(connector, &conn_iter) {
> + struct intel_encoder *encoder;
> +
> if (connector->connector_type !=
> DRM_MODE_CONNECTOR_DisplayPort)
> continue;
>
> - if (connector->status == connector_status_connected &&
> - connector->encoder != NULL) {
> - intel_dp = enc_to_intel_dp(connector->encoder);
> + encoder = to_intel_encoder(connector->encoder);
> + if (encoder && encoder->type == INTEL_OUTPUT_DP_MST)
> + continue;
> +
> + if (encoder && connector->status == connector_status_connected)
> {
> + intel_dp = enc_to_intel_dp(&encoder->base);
> if (intel_dp->compliance.test_active)
> seq_puts(m, "1");
> else
> @@ -3858,13 +3863,18 @@ static int i915_displayport_test_data_show(struct
> seq_file *m, void *data)
>
> drm_connector_list_iter_begin(dev, &conn_iter);
> drm_for_each_connector_iter(connector, &conn_iter) {
> + struct intel_encoder *encoder;
> +
> if (connector->connector_type !=
> DRM_MODE_CONNECTOR_DisplayPort)
> continue;
>
> - if (connector->status == connector_status_connected &&
> - connector->encoder != NULL) {
> - intel_dp = enc_to_intel_dp(connector->encoder);
> + encoder = to_intel_encoder(connector->encoder);
> + if (encoder && encoder->type == INTEL_OUTPUT_DP_MST)
> + continue;
> +
> + if (encoder && connector->status == connector_status_connected)
> {
> + intel_dp = enc_to_intel_dp(&encoder->base);
> if (intel_dp->compliance.test_type ==
> DP_TEST_LINK_EDID_READ)
> seq_printf(m, "%lx",
> @@ -3911,13 +3921,18 @@ static int i915_displayport_test_type_show(struct
> seq_file *m, void *data)
>
> drm_connector_list_iter_begin(dev, &conn_iter);
> drm_for_each_connector_iter(connector, &conn_iter) {
> + struct intel_encoder *encoder;
> +
> if (connector->connector_type !=
> DRM_MODE_CONNECTOR_DisplayPort)
> continue;
>
> - if (connector->status == connector_status_connected &&
> - connector->encoder != NULL) {
> - intel_dp = enc_to_intel_dp(connector->encoder);
> + encoder = to_intel_encoder(connector->encoder);
> + if (encoder && encoder->type == INTEL_OUTPUT_DP_MST)
> + continue;
> +
> + if (encoder && connector->status == connector_status_connected)
> {
> + intel_dp = enc_to_intel_dp(&encoder->base);
> seq_printf(m, "%02lx", intel_dp->compliance.test_type);
> } else
> seq_puts(m, "0");
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