From 94b909a37b350b529839112b550dc517e3abc99c Mon Sep 17 00:00:00 2001
From: Taimur Hassan <Syed.Hassan@amd.com>
Date: Tue, 13 Sep 2022 16:04:06 -0400
Subject: drm/amd/display: Avoid avoid unnecessary pixel rate divider
programming
Git-commit: 783d446749c09eb34178cb8600a9a93d3b99e35d
Patch-mainline: v6.0
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]
Programming pixel rate divider when FIFO is enabled can cause FIFO error.
[How]
Skip divider programming when divider values are the same to prevent FIFO
error.
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Taimur Hassan <Syed.Hassan@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>
---
.../drm/amd/display/dc/dcn314/dcn314_dccg.c | 47 +++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c
index 232cc15979dd..60540864e028 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn314/dcn314_dccg.c
@@ -45,6 +45,48 @@
#define DC_LOGGER \
dccg->ctx->logger
+static void dccg314_get_pixel_rate_div(
+ struct dccg *dccg,
+ uint32_t otg_inst,
+ enum pixel_rate_div *k1,
+ enum pixel_rate_div *k2)
+{
+ struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
+ uint32_t val_k1 = PIXEL_RATE_DIV_NA, val_k2 = PIXEL_RATE_DIV_NA;
+
+ *k1 = PIXEL_RATE_DIV_NA;
+ *k2 = PIXEL_RATE_DIV_NA;
+
+ switch (otg_inst) {
+ case 0:
+ REG_GET_2(OTG_PIXEL_RATE_DIV,
+ OTG0_PIXEL_RATE_DIVK1, &val_k1,
+ OTG0_PIXEL_RATE_DIVK2, &val_k2);
+ break;
+ case 1:
+ REG_GET_2(OTG_PIXEL_RATE_DIV,
+ OTG1_PIXEL_RATE_DIVK1, &val_k1,
+ OTG1_PIXEL_RATE_DIVK2, &val_k2);
+ break;
+ case 2:
+ REG_GET_2(OTG_PIXEL_RATE_DIV,
+ OTG2_PIXEL_RATE_DIVK1, &val_k1,
+ OTG2_PIXEL_RATE_DIVK2, &val_k2);
+ break;
+ case 3:
+ REG_GET_2(OTG_PIXEL_RATE_DIV,
+ OTG3_PIXEL_RATE_DIVK1, &val_k1,
+ OTG3_PIXEL_RATE_DIVK2, &val_k1);
+ break;
+ default:
+ BREAK_TO_DEBUGGER();
+ return;
+ }
+
+ *k1 = (enum pixel_rate_div)val_k1;
+ *k2 = (enum pixel_rate_div)val_k2;
+}
+
static void dccg314_set_pixel_rate_div(
struct dccg *dccg,
uint32_t otg_inst,
@@ -52,6 +94,11 @@ static void dccg314_set_pixel_rate_div(
enum pixel_rate_div k2)
{
struct dcn_dccg *dccg_dcn = TO_DCN_DCCG(dccg);
+ enum pixel_rate_div cur_k1 = PIXEL_RATE_DIV_NA, cur_k2 = PIXEL_RATE_DIV_NA;
+
+ dccg314_get_pixel_rate_div(dccg, otg_inst, &cur_k1, &cur_k2);
+ if (k1 == PIXEL_RATE_DIV_NA || k2 == PIXEL_RATE_DIV_NA || (k1 == cur_k1 && k2 == cur_k2))
+ return;
switch (otg_inst) {
case 0:
--
2.38.1