From 256738f63d42c7db1b208ae8c6120d954bddb5c8 Mon Sep 17 00:00:00 2001 From: Ryan Seto Date: Fri, 28 Feb 2025 14:24:57 -0500 Subject: [PATCH] drm/amd/display: Prevent VStartup Overflow [ Upstream commit 29c1c20496a7a9bafe2bc2f833d69aa52e0f2c2d ] [Why] For some VR headsets with large blanks, it's possible to overflow the OTG_VSTARTUP_PARAM:VSTARTUP_START register. This can lead to incorrect DML calculations and underflow downstream. [How] Min the calcualted max_vstartup_lines with the max value of the register. Reviewed-by: Dillon Varone Signed-off-by: Ryan Seto Signed-off-by: Tom Chung Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- .../display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c index ecfa3c898e09d..4285cb7fcbe71 100644 --- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c +++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c @@ -12,6 +12,7 @@ #define DML2_MAX_FMT_420_BUFFER_WIDTH 4096 #define DML_MAX_NUM_OF_SLICES_PER_DSC 4 #define ALLOW_SDPIF_RATE_LIMIT_PRE_CSTATE +#define DML_MAX_VSTARTUP_START 1023 const char *dml2_core_internal_bw_type_str(enum dml2_core_internal_bw_type bw_type) { @@ -3648,6 +3649,7 @@ static unsigned int CalculateMaxVStartup( dml2_printf("DML::%s: vblank_avail = %u\n", __func__, vblank_avail); dml2_printf("DML::%s: max_vstartup_lines = %u\n", __func__, max_vstartup_lines); #endif + max_vstartup_lines = (unsigned int)math_min2(max_vstartup_lines, DML_MAX_VSTARTUP_START); return max_vstartup_lines; } -- 2.47.3