This is a note to let you know that I've just added the patch titled
drm/amd/display: fix num_ways overflow error
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-fix-num_ways-overflow-error.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit da85f78ec4f7a17f8c7a6a0d4a8bf7916cfeb906
Author: Samson Tam <samson.tam@xxxxxxx>
Date: Thu Oct 5 01:31:12 2023 -0400
drm/amd/display: fix num_ways overflow error
[ Upstream commit 79f3f1b66753b3a3a269d73676bf50987921f267 ]
[Why]
Helper function calculates num_ways using 32-bit. But is
returned as 8-bit. If num_ways exceeds 8-bit, then it
reports back the incorrect num_ways and erroneously
uses MALL when it should not
[How]
Make returned value 32-bit and convert after it checks
against caps.cache_num_ways, which is under 8-bit
Reviewed-by: Alvin Lee <alvin.lee2@xxxxxxx>
Acked-by: Roman Li <roman.li@xxxxxxx>
Signed-off-by: Samson Tam <samson.tam@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
index 018376146d977..be59e1c02f8aa 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_hwseq.c
@@ -214,7 +214,7 @@ static bool dcn32_check_no_memory_request_for_cab(struct dc *dc)
static uint32_t dcn32_calculate_cab_allocation(struct dc *dc, struct dc_state *ctx)
{
int i;
- uint8_t num_ways = 0;
+ uint32_t num_ways = 0;
uint32_t mall_ss_size_bytes = 0;
mall_ss_size_bytes = ctx->bw_ctx.bw.dcn.mall_ss_size_bytes;
@@ -244,7 +244,8 @@ static uint32_t dcn32_calculate_cab_allocation(struct dc *dc, struct dc_state *c
bool dcn32_apply_idle_power_optimizations(struct dc *dc, bool enable)
{
union dmub_rb_cmd cmd;
- uint8_t ways, i;
+ uint8_t i;
+ uint32_t ways;
int j;
bool mall_ss_unsupported = false;
struct dc_plane_state *plane = NULL;
@@ -304,7 +305,7 @@ bool dcn32_apply_idle_power_optimizations(struct dc *dc, bool enable)
cmd.cab.header.type = DMUB_CMD__CAB_FOR_SS;
cmd.cab.header.sub_type = DMUB_CMD__CAB_DCN_SS_FIT_IN_CAB;
cmd.cab.header.payload_bytes = sizeof(cmd.cab) - sizeof(cmd.cab.header);
- cmd.cab.cab_alloc_ways = ways;
+ cmd.cab.cab_alloc_ways = (uint8_t)ways;
dm_execute_dmub_cmd(dc->ctx, &cmd, DM_DMUB_WAIT_TYPE_NO_WAIT);
