drm/amd/display: Check correct bounds for stream encoder instances for DCN303

commit 89b008222c2bf21e50219725caed31590edfd9d1 upstream.

[Why & How]
eng_id for DCN303 cannot be more than 1, since we have only two
instances of stream encoders.

Check the correct boundary condition for engine ID for DCN303 prevent
the potential out of bounds access.

Fixes: cd6d421e3d1a ("drm/amd/display: Initial DC support for Beige Goby")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Chris Park <Chris.Park@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c b/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
index 76f863eb86ef2043daaed79bcda944d508c4bf01..401ccc676ae9ae38236ce81a67d218388d765ba3 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
@@ -372,7 +372,7 @@ static struct stream_encoder *dcn303_stream_encoder_create(enum engine_id eng_id
        int afmt_inst;
 
        /* Mapping of VPG, AFMT, DME register blocks to DIO block instance */
-       if (eng_id <= ENGINE_ID_DIGE) {
+       if (eng_id <= ENGINE_ID_DIGB) {
                vpg_inst = eng_id;
                afmt_inst = eng_id;
        } else