From e643c7d036d322c2898c9e65e466d75d0c708dc2 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Sun, 26 Jan 2014 00:20:21 -0800 Subject: [PATCH] i965: Implement a CS stall workaround on Broadwell. According to the latest documentation, any PIPE_CONTROL with the "Command Streamer Stall" bit set must also have another bit set, with five different options: - Render Target Cache Flush - Depth Cache Flush - Stall at Pixel Scoreboard - Post-Sync Operation - Depth Stall I chose "Stall at Pixel Scoreboard" since we've used it effectively in the past, but the choice is fairly arbitrary. Implementing this in the PIPE_CONTROL emit helpers ensures that the workaround will always take effect when it ought to. Apparently, this workaround may be necessary on older hardware as well; for now I've only added it to Broadwell as it's absolutely necessary there. Subsequent patches could add it to older platforms, provided someone tests it there. v2: Only flag "Stall at Pixel Scoreboard" when none of the other bits are set (suggested by Ian Romanick). v3: Prefix the function with "gen8" (requested by Eric). Signed-off-by: Kenneth Graunke Reviewed-by: Ian Romanick (v2) Reviewed-by: Eric Anholt --- src/mesa/drivers/dri/i965/intel_batchbuffer.c | 36 +++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c b/src/mesa/drivers/dri/i965/intel_batchbuffer.c index 46242681229..a06f298bafd 100644 --- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c +++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c @@ -431,6 +431,38 @@ intel_batchbuffer_data(struct brw_context *brw, brw->batch.used += bytes >> 2; } +/** + * According to the latest documentation, any PIPE_CONTROL with the + * "Command Streamer Stall" bit set must also have another bit set, + * with five different options: + * + * - Render Target Cache Flush + * - Depth Cache Flush + * - Stall at Pixel Scoreboard + * - Post-Sync Operation + * - Depth Stall + * + * I chose "Stall at Pixel Scoreboard" since we've used it effectively + * in the past, but the choice is fairly arbitrary. + */ +static void +gen8_add_cs_stall_workaround_bits(uint32_t *flags) +{ + uint32_t wa_bits = PIPE_CONTROL_WRITE_FLUSH | + PIPE_CONTROL_DEPTH_CACHE_FLUSH | + PIPE_CONTROL_WRITE_IMMEDIATE | + PIPE_CONTROL_WRITE_DEPTH_COUNT | + PIPE_CONTROL_WRITE_TIMESTAMP | + PIPE_CONTROL_STALL_AT_SCOREBOARD | + PIPE_CONTROL_DEPTH_STALL; + + /* If we're doing a CS stall, and don't already have one of the + * workaround bits set, add "Stall at Pixel Scoreboard." + */ + if ((*flags & PIPE_CONTROL_CS_STALL) != 0 && (*flags & wa_bits) == 0) + *flags |= PIPE_CONTROL_STALL_AT_SCOREBOARD; +} + /** * Emit a PIPE_CONTROL with various flushing flags. * @@ -441,6 +473,8 @@ void brw_emit_pipe_control_flush(struct brw_context *brw, uint32_t flags) { if (brw->gen >= 8) { + gen8_add_cs_stall_workaround_bits(&flags); + BEGIN_BATCH(6); OUT_BATCH(_3DSTATE_PIPE_CONTROL | (6 - 2)); OUT_BATCH(flags); @@ -481,6 +515,8 @@ brw_emit_pipe_control_write(struct brw_context *brw, uint32_t flags, uint32_t imm_lower, uint32_t imm_upper) { if (brw->gen >= 8) { + gen8_add_cs_stall_workaround_bits(&flags); + BEGIN_BATCH(6); OUT_BATCH(_3DSTATE_PIPE_CONTROL | (6 - 2)); OUT_BATCH(flags); -- 2.30.2