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Commit a874b6a3 authored by Maarten Lankhorst's avatar Maarten Lankhorst
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drm/i915: Prevent kernel panic when reading/writing compliance debugfs files, v2. 



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.

Also fix the write for the DP compliance file in the same way.

Changes since v1:
- Fix i915_displayport_test_active_write too. (DK)

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: default avatarDhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170626081835.24251-1-maarten.lankhorst@linux.intel.com
parent 987f8c44

drivers/gpu/drm/i915/i915_debugfs.c

+32 −12
Original line number Diff line number Diff line
@@ -3778,13 +3778,18 @@ static ssize_t i915_displayport_test_active_write(struct file *file, 


	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);

			status = kstrtoint(input_buffer, 10, &val);

			if (status < 0)

				break;
@@ -3816,13 +3821,18 @@ 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
@@ -3862,13 +3872,18 @@ 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",
@@ -3915,13 +3930,18 @@ 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");