From 1c57014325ef2b62459c8482768a842f9c40cd0c Mon Sep 17 00:00:00 2001 From: Gareth Yu Date: Fri, 9 May 2025 17:25:39 +0800 Subject: [PATCH] drm/i915/dsi: Enforce pipeline flush with DSI HS transfer With all of the boundary conditions when streaming the commands B2B in our validation (part of the reason we added the flush), the Flush effectively serializes the transmission of each command enqueued within the command dispatcher to one per V. Blank line which simplifies the behavior of the High Speed Arbitration. So, unless we absolutely have to burst these to the Sink, we should be using the Pipeline Flush bit to serialize the commands. Bspec: 19742, 50193 Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14247 Cc: Suraj Kandpal Cc: Jani Nikula Signed-off-by: Gareth Yu Link: https://lore.kernel.org/r/20250509092539.763389-1-gareth.yu@intel.com Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/display/icl_dsi.c | 4 ++-- drivers/gpu/drm/i915/display/icl_dsi_regs.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c index ca7033251e916..28dab9320aedd 100644 --- a/drivers/gpu/drm/i915/display/icl_dsi.c +++ b/drivers/gpu/drm/i915/display/icl_dsi.c @@ -192,12 +192,12 @@ static int dsi_send_pkt_hdr(struct intel_dsi_host *host, else tmp &= ~PAYLOAD_PRESENT; - tmp &= ~VBLANK_FENCE; + tmp &= ~(VBLANK_FENCE | LP_DATA_TRANSFER | PIPELINE_FLUSH); if (enable_lpdt) tmp |= LP_DATA_TRANSFER; else - tmp &= ~LP_DATA_TRANSFER; + tmp |= PIPELINE_FLUSH; tmp &= ~(PARAM_WC_MASK | VC_MASK | DT_MASK); tmp |= ((packet->header[0] & VC_MASK) << VC_SHIFT); diff --git a/drivers/gpu/drm/i915/display/icl_dsi_regs.h b/drivers/gpu/drm/i915/display/icl_dsi_regs.h index d4845ac65acce..b601b7632339a 100644 --- a/drivers/gpu/drm/i915/display/icl_dsi_regs.h +++ b/drivers/gpu/drm/i915/display/icl_dsi_regs.h @@ -272,6 +272,7 @@ #define PAYLOAD_PRESENT (1 << 31) #define LP_DATA_TRANSFER (1 << 30) #define VBLANK_FENCE (1 << 29) +#define PIPELINE_FLUSH (1 << 28) #define PARAM_WC_MASK (0xffff << 8) #define PARAM_WC_LOWER_SHIFT 8 #define PARAM_WC_UPPER_SHIFT 16 -- 2.47.2