fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2025-12-24 19:40:10 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

i965: Implement a CS stall workaround on Broadwell.

Browse source 
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 <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> (v2)
Reviewed-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Kenneth Graunke 2014-01-26 00:20:21 -08:00
parent 741782b594
commit e643c7d036
1 changed files with 36 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
src/mesa/drivers/dri/i965/intel_batchbuffer.c
View file

@ -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);