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Commit 53b91408 authored by Damien Lespiau's avatar Damien Lespiau Committed by Daniel Vetter
Browse files

drm/i915: Don't attempt to read an unitialized stack value 



If intel_sdvo_get_value() fails here, val is unitialized and the cross
check will compare the pipe config multiplier with a bogus value.

Instead, only set encoder_pixel_multiplier when the sdvo command has
been successful. The cross check will compare the pipe config value with
0 otherwise.

v2: Do the cross check with the initial value of encoder_pixel_multiplier (0)
if the sdvo command fails (and thus keep the warning) (Daniel Vetter)

Signed-off-by: default avatarDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 08e2a7de

drivers/gpu/drm/i915/intel_sdvo.c

+13 −11
Original line number Original line Diff line number Diff line
@@ -1357,7 +1357,8 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder, 
	}

	}





	/* Cross check the port pixel multiplier with the sdvo encoder state. */

	/* Cross check the port pixel multiplier with the sdvo encoder state. */

	intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_CLOCK_RATE_MULT, &val, 1);

	if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_CLOCK_RATE_MULT,

				 &val, 1)) {

		switch (val) {

		switch (val) {

		case SDVO_CLOCK_RATE_MULT_1X:

		case SDVO_CLOCK_RATE_MULT_1X:

			encoder_pixel_multiplier = 1;

			encoder_pixel_multiplier = 1;
@@ -1369,6 +1370,7 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder, 
			encoder_pixel_multiplier = 4;

			encoder_pixel_multiplier = 4;

			break;

			break;

		}

		}

	}





	WARN(encoder_pixel_multiplier != pipe_config->pixel_multiplier,

	WARN(encoder_pixel_multiplier != pipe_config->pixel_multiplier,

	     "SDVO pixel multiplier mismatch, port: %i, encoder: %i\n",

	     "SDVO pixel multiplier mismatch, port: %i, encoder: %i\n",