From dcd3976dc51189875a40713ec9b0151b70e7e5be Mon Sep 17 00:00:00 2001
From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Date: Tue, 12 Jul 2022 14:32:45 -0400
Subject: drm/amd/display: Guard against zero memory channels
Git-commit: a7cefb0b40dcfdafedc54a3ba659327d0336956d
Patch-mainline: v6.0-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225 jsc#PED-2849
[Why]
If BIOS doesn't specify number of memory channels then bandwidth
validation will fail due to insufficient BW in DML.
[How]
If BIOS is setting zero channels then use the default in the table.
If no entry is in the table and no BIOS value is specified then
throw an ASSERT for future developers to look into.
Reviewed-by: Michael Strauss <Michael.Strauss@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
index 450ebd838505..56ada096c89d 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c
@@ -1916,8 +1916,11 @@ static void dcn314_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *b
dcn3_14_ip.max_num_otg = dc->res_pool->res_cap->num_timing_generator;
dcn3_14_ip.max_num_dpp = dc->res_pool->pipe_count;
- dcn3_14_soc.num_chans = bw_params->num_channels;
+ if (bw_params->num_channels > 0)
+ dcn3_14_soc.num_chans = bw_params->num_channels;
+
+ ASSERT(dcn3_14_soc.num_chans);
ASSERT(clk_table->num_entries);
/* Prepass to find max clocks independent of voltage level. */
--
2.38.1