From: Damien Lespiau Date: Fri, 12 Jul 2013 15:24:40 +0000 (+0100) Subject: drm/i915: Don't attempt to read an unitialized stack value X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=53b914084950e5766b40228c4e08706e28745fa5;p=linux-beck.git 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: Damien Lespiau Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c index 8415d6a610dd..798df114cfd3 100644 --- a/drivers/gpu/drm/i915/intel_sdvo.c +++ b/drivers/gpu/drm/i915/intel_sdvo.c @@ -1357,17 +1357,19 @@ static void intel_sdvo_get_config(struct intel_encoder *encoder, } /* 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); - switch (val) { - case SDVO_CLOCK_RATE_MULT_1X: - encoder_pixel_multiplier = 1; - break; - case SDVO_CLOCK_RATE_MULT_2X: - encoder_pixel_multiplier = 2; - break; - case SDVO_CLOCK_RATE_MULT_4X: - encoder_pixel_multiplier = 4; - break; + if (intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_CLOCK_RATE_MULT, + &val, 1)) { + switch (val) { + case SDVO_CLOCK_RATE_MULT_1X: + encoder_pixel_multiplier = 1; + break; + case SDVO_CLOCK_RATE_MULT_2X: + encoder_pixel_multiplier = 2; + break; + case SDVO_CLOCK_RATE_MULT_4X: + encoder_pixel_multiplier = 4; + break; + } } WARN(encoder_pixel_multiplier != pipe_config->pixel_multiplier,