From 5b543124928cd588540dd8d0a5ecad1cef222291 Mon Sep 17 00:00:00 2001 From: Ashley Thomas Date: Mon, 12 Oct 2020 21:33:27 -0700 Subject: [PATCH] drm/amd/display: fail instead of div by zero/bugcheck [why] If pbn_per_slot is 0, fail instead of dividing by zero and bugchecking. [how] Check for zero divisor before division operation. Signed-off-by: Ashley Thomas Reviewed-by: Wyatt Wood Acked-by: Qingqing Zhuo Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_debug.c | 2 ++ drivers/gpu/drm/amd/display/dc/core/dc_link.c | 4 ++++ drivers/gpu/drm/amd/display/dc/inc/core_status.h | 1 + 3 files changed, 7 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_debug.c b/drivers/gpu/drm/amd/display/dc/core/dc_debug.c index 7977e28390650..21be2a684393a 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_debug.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_debug.c @@ -420,6 +420,8 @@ char *dc_status_to_str(enum dc_status status) return "Fail clk below required CFG (hard_min in PPLIB)"; case DC_NOT_SUPPORTED: return "The operation is not supported."; + case DC_UNSUPPORTED_VALUE: + return "The value specified is not supported."; case DC_ERROR_UNEXPECTED: return "Unexpected error"; } diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index 3900c81699a06..6b8bc8dde6ea6 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -2952,6 +2952,10 @@ enum dc_status dc_link_allocate_mst_payload(struct pipe_ctx *pipe_ctx) /* slot X.Y for only current stream */ pbn_per_slot = get_pbn_per_slot(stream); + if (pbn_per_slot.value == 0) { + DC_LOG_ERROR("Failure: pbn_per_slot==0 not allowed. Cannot continue, returning DC_UNSUPPORTED_VALUE.\n"); + return DC_UNSUPPORTED_VALUE; + } pbn = get_pbn_from_timing(pipe_ctx); avg_time_slots_per_mtp = dc_fixpt_div(pbn, pbn_per_slot); diff --git a/drivers/gpu/drm/amd/display/dc/inc/core_status.h b/drivers/gpu/drm/amd/display/dc/inc/core_status.h index 714593a155905..d34b0b0eea655 100644 --- a/drivers/gpu/drm/amd/display/dc/inc/core_status.h +++ b/drivers/gpu/drm/amd/display/dc/inc/core_status.h @@ -51,6 +51,7 @@ enum dc_status { DC_FAIL_CLK_BELOW_CFG_REQUIRED = 23, /*THIS IS hard_min in PPLIB*/ DC_NOT_SUPPORTED = 24, + DC_UNSUPPORTED_VALUE = 25, DC_ERROR_UNEXPECTED = -1 }; -- 2.39.5