[Mesa-dev] [PATCH v2 3/5] anv: Add support for the PMA fix on Broadwell
Jason Ekstrand
jason at jlekstrand.net
Thu Feb 9 02:27:52 UTC 2017
On Wed, Feb 8, 2017 at 5:34 PM, Nanley Chery <nanleychery at gmail.com> wrote:
> On Thu, Feb 02, 2017 at 01:26:05PM -0800, Jason Ekstrand wrote:
> > In order to get good performance numbers for this, I had to hack up the
> > driver to whack wm_prog_data::uses_kill to true to emulate a discard and
> > used the Sascha "shadowmapping" demo. Setting uses_kill to true dropped
> > the framerate on the demo by 25-30%. Enabling the PMA fix brought it
> > back up to around 90% of the original framerate. This doesn't seem to
> > really impact Dota 2; probably because it doesn't use 16-bit depth.
> >
> > Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> > ---
> > src/intel/vulkan/TODO | 1 -
> > src/intel/vulkan/anv_cmd_buffer.c | 2 +
> > src/intel/vulkan/anv_genX.h | 3 +
> > src/intel/vulkan/anv_private.h | 17 +++++
> > src/intel/vulkan/gen7_cmd_buffer.c | 7 ++
> > src/intel/vulkan/gen8_cmd_buffer.c | 133 ++++++++++++++++++++++++++++++
> +++++++
> > src/intel/vulkan/genX_blorp_exec.c | 5 ++
> > src/intel/vulkan/genX_cmd_buffer.c | 15 ++++-
> > src/intel/vulkan/genX_pipeline.c | 38 +++++++++++
> > 9 files changed, 219 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/intel/vulkan/TODO b/src/intel/vulkan/TODO
> > index 38acc0d..f8b73a1 100644
> > --- a/src/intel/vulkan/TODO
> > +++ b/src/intel/vulkan/TODO
> > @@ -12,5 +12,4 @@ Performance:
> > - Compressed multisample support
> > - Pushing pieces of UBOs?
> > - Enable guardband clipping
> > - - pma stall workaround
> > - Use soft-pin to avoid relocations
> > diff --git a/src/intel/vulkan/anv_cmd_buffer.c
> b/src/intel/vulkan/anv_cmd_buffer.c
> > index 5886fa6..8c08f8d 100644
> > --- a/src/intel/vulkan/anv_cmd_buffer.c
> > +++ b/src/intel/vulkan/anv_cmd_buffer.c
> > @@ -135,6 +135,8 @@ anv_cmd_state_reset(struct anv_cmd_buffer
> *cmd_buffer)
> > state->restart_index = UINT32_MAX;
> > state->dynamic = default_dynamic_state;
> > state->need_query_wa = true;
> > + state->pma_fix_enabled = false;
> > + state->hiz_enabled = false;
> >
> > if (state->attachments != NULL) {
> > vk_free(&cmd_buffer->pool->alloc, state->attachments);
> > diff --git a/src/intel/vulkan/anv_genX.h b/src/intel/vulkan/anv_genX.h
> > index d04fe38..67147b0 100644
> > --- a/src/intel/vulkan/anv_genX.h
> > +++ b/src/intel/vulkan/anv_genX.h
> > @@ -55,6 +55,9 @@ void genX(cmd_buffer_flush_dynamic_state)(struct
> anv_cmd_buffer *cmd_buffer);
> >
> > void genX(cmd_buffer_flush_compute_state)(struct anv_cmd_buffer
> *cmd_buffer);
> >
> > +void genX(cmd_buffer_enable_pma_fix)(struct anv_cmd_buffer *cmd_buffer,
> > + bool enable);
> > +
> > void
> > genX(emit_urb_setup)(struct anv_device *device, struct anv_batch *batch,
> > const struct gen_l3_config *l3_config,
> > diff --git a/src/intel/vulkan/anv_private.h b/src/intel/vulkan/anv_
> private.h
> > index 4fe3ebc..6efe4ea 100644
> > --- a/src/intel/vulkan/anv_private.h
> > +++ b/src/intel/vulkan/anv_private.h
> > @@ -1163,6 +1163,20 @@ struct anv_cmd_state {
> > bool need_query_wa;
> >
> > /**
> > + * Whether or not the gen8 PMA fix is enabled. We ensure that, at
> the top
> > + * of any command buffer it disabled by disabling it in
> EndCommandBuffer
> ^
> is?
>
> > + * and before invoking the secondary in ExecuteCommands.
> > + */
> > + bool pma_fix_enabled;
> > +
> > + /**
> > + * Whether or not we now for certain that HiZ is enabled for the
> current
> ^
> know
>
> > + * subpass. If, for whatever reason, we are unsure as to whether
> HiZ is
> > + * enabled or not, this will be false.
> > + */
> > + bool hiz_enabled;
> > +
> > + /**
> > * Array length is anv_cmd_state::pass::attachment_count. Array
> content is
> > * valid only when recording a render pass instance.
> > */
> > @@ -1465,8 +1479,11 @@ struct anv_pipeline {
> >
> > uint32_t cs_right_mask;
> >
> > + bool writes_depth;
> > + bool depth_test_enable;
> > bool writes_stencil;
> > bool depth_clamp_enable;
> > + bool kill_pixel;
> >
> > struct {
> > uint32_t sf[7];
> > diff --git a/src/intel/vulkan/gen7_cmd_buffer.c
> b/src/intel/vulkan/gen7_cmd_buffer.c
> > index 013ed87..c1a25e8 100644
> > --- a/src/intel/vulkan/gen7_cmd_buffer.c
> > +++ b/src/intel/vulkan/gen7_cmd_buffer.c
> > @@ -260,6 +260,13 @@ genX(cmd_buffer_flush_dynamic_state)(struct
> anv_cmd_buffer *cmd_buffer)
> > cmd_buffer->state.dirty = 0;
> > }
> >
> > +void
> > +genX(cmd_buffer_enable_pma_fix)(struct anv_cmd_buffer *cmd_buffer,
> > + bool enable)
> > +{
> > + /* The NP PMA fix doesn't exist on gen7 */
> > +}
> > +
> > void genX(CmdSetEvent)(
> > VkCommandBuffer commandBuffer,
> > VkEvent event,
> > diff --git a/src/intel/vulkan/gen8_cmd_buffer.c
> b/src/intel/vulkan/gen8_cmd_buffer.c
> > index 8c8de62..271ab3f 100644
> > --- a/src/intel/vulkan/gen8_cmd_buffer.c
> > +++ b/src/intel/vulkan/gen8_cmd_buffer.c
> > @@ -155,6 +155,135 @@ __emit_sf_state(struct anv_cmd_buffer *cmd_buffer)
> > #endif
> >
> > void
> > +genX(cmd_buffer_enable_pma_fix)(struct anv_cmd_buffer *cmd_buffer,
> bool enable)
> > +{
> > +#if GEN_GEN == 8
> > + if (cmd_buffer->state.pma_fix_enabled == enable)
> > + return;
> > +
> > + anv_batch_emit(&cmd_buffer->batch, GENX(PIPE_CONTROL), pc) {
> > + pc.DepthCacheFlushEnable = true;
> > + pc.CommandStreamerStallEnable = true;
> > + pc.RenderTargetCacheFlushEnable = true;
>
> Instead of flushing the depth and RT caches, what do you think about
> implementing a stall that writes 0 to the workaround bo? That should
> consume less bandwidth.
>
> To make the pipeline idle, flushing the caches shouldn't be necessary,
> we should be able to do it with a valid pipecontrol packet that has the
> CS stall bit set.
>
Without having an extremely good idea of how these bits interact with
caching, I'm very reluctant to try too hard to over-optimize the pipe
control.
> The BDW PRM states:
>
> If the stall bit is set, the command streamer waits until the pipe is
> completely flushed.
>
It waits until whatever flush/stall operation you gave it is finished. You
also need to specify a stall/flush operation. If you just do a depth stall
for instance and no depth reads/writes are in-flight, I don't think it
actually stalls at all. We may be able to use StallAtPixelScoreboard
instead but, again, I don't know for sure how this interacts with caches.
> > + }
> > +
> > + uint32_t cache_mode;
> > + anv_pack_struct(&cache_mode, GENX(CACHE_MODE_1),
> > + .NPPMAFixEnable = enable,
> > + .NPEarlyZFailsDisableMask = enable,
> ^
> I don't think you intended to set the mask here. It should be:
>
> .NPEarlyZFailsDisable = enable,
>
> Does fixing this impact your FPS measurements significantly?
>
Thanks for catching that! I'm a bit surprised that it worked at all. I'll
definitely re-measure.
> > + .NPPMAFixEnableMask = true,
> > + .NPEarlyZFailsDisableMask = true);
> > + anv_batch_emit(&cmd_buffer->batch, GENX(MI_LOAD_REGISTER_IMM), lri)
> {
> > + lri.RegisterOffset = GENX(CACHE_MODE_1_num);
> > + lri.DataDWord = cache_mode;
> > + }
> > +
> > + /* After the LRI, a PIPE_CONTROL with both the Depth Stall and Depth
> Cache
> > + * Flush bits is often necessary. We do it regardless because it's
> easier.
> > + * The render cache flush is also necessary if stencil writes are
> enabled.
> > + */
>
> I couldn't find a requirement to flush these specific caches in the
> docs, but I did find:
>
Both of these flushes are documented in the bspec (not PRM) docs for
PIPE_CONTROL.
> To ensure this command gets executed before upcoming commands in the
> ring, either a stalling pipecontrol should be sent after this
> command, or MMIO 0x20C0 bit 7 should be set to 1.
>
> Perhaps we could use the flush I suggested earlier?
>
> > + anv_batch_emit(&cmd_buffer->batch, GENX(PIPE_CONTROL), pc) {
> > + pc.DepthStallEnable = true;
> > + pc.DepthCacheFlushEnable = true;
> > + pc.RenderTargetCacheFlushEnable = true;
> > + }
> > +
> > + cmd_buffer->state.pma_fix_enabled = enable;
> > +#endif /* GEN_GEN == 8 */
> > +}
> > +
> > +static inline bool
> > +want_depth_pma_fix(struct anv_cmd_buffer *cmd_buffer)
> > +{
> > + assert(GEN_GEN == 8);
> > +
> > + /* From the Broadwell PRM Vol. 2c CACHE_MODE_1::NP_PMA_FIX_ENABLE:
> > + *
> > + * SW must set this bit in order to enable this fix when following
> > + * expression is TRUE.
> > + *
> > + * 3DSTATE_WM::ForceThreadDispatch != 1 &&
> > + * !(3DSTATE_RASTER::ForceSampleCount != NUMRASTSAMPLES_0) &&
> > + * (3DSTATE_DEPTH_BUFFER::SURFACE_TYPE != NULL) &&
> > + * (3DSTATE_DEPTH_BUFFER::HIZ Enable) &&
> > + * !(3DSTATE_WM::EDSC_Mode == EDSC_PREPS) &&
> > + * (3DSTATE_PS_EXTRA::PixelShaderValid) &&
> > + * !(3DSTATE_WM_HZ_OP::DepthBufferClear ||
> > + * 3DSTATE_WM_HZ_OP::DepthBufferResolve ||
> > + * 3DSTATE_WM_HZ_OP::Hierarchical Depth Buffer Resolve Enable ||
> > + * 3DSTATE_WM_HZ_OP::StencilBufferClear) &&
> > + * (3DSTATE_WM_DEPTH_STENCIL::DepthTestEnable) &&
> > + * (((3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > + * 3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > + * 3DSTATE_PS_BLEND::AlphaToCoverageEnable ||
> > + * 3DSTATE_PS_BLEND::AlphaTestEnable ||
> > + * 3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable) &&
> > + * 3DSTATE_WM::ForceKillPix != ForceOff &&
> > + * ((3DSTATE_WM_DEPTH_STENCIL::DepthWriteEnable &&
> > + * 3DSTATE_DEPTH_BUFFER::DEPTH_WRITE_ENABLE) ||
> > + * (3DSTATE_WM_DEPTH_STENCIL::Stencil Buffer Write Enable &&
> > + * 3DSTATE_DEPTH_BUFFER::STENCIL_WRITE_ENABLE &&
> > + * 3DSTATE_STENCIL_BUFFER::STENCIL_BUFFER_ENABLE))) ||
> > + * (3DSTATE_PS_EXTRA:: Pixel Shader Computed Depth mode !=
> PSCDEPTH_OFF))
> > + *
> > + * This function only takes care of the pipeline parts of the
> equation.
>
> Which parts are the pipeline parts? It looks like you take care of the
> entire equation in this function.
>
Yes, I do.
> > + */
> > +
> > + /* These are always true:
> > + * 3DSTATE_WM::ForceThreadDispatch != 1 &&
> > + * !(3DSTATE_RASTER::ForceSampleCount != NUMRASTSAMPLES_0)
> > + */
>
> I couldn't quite understand what ForcedSampleCount does from looking at
> the HW docs. If you know, could you tell me what this does and why it
> wouldn't change under any circumstance in the future? Otherwise, I
> think we should put an assertion where we assign ForcedSampleCount and
> reference this PMA optimization.
>
Honestly, I'm not 100% sure what it's for. I think it lets you make the
rasterizer run at a different number of samples than the underlying
surface. We've never used this bit in Vulkan or GL. Also, there's no flag
for us to assert on.
> > +
> > + /* We only enable the PMA fix if we know for certain that HiZ is
> enabled.
> > + * If we don't know whether HiZ is enabled or not, we disable the
> PMA fix
> > + * and there is no harm.
> > + *
> > + * (3DSTATE_DEPTH_BUFFER::SURFACE_TYPE != NULL) &&
> > + * 3DSTATE_DEPTH_BUFFER::HIZ Enable
> > + */
> > + if (!cmd_buffer->state.hiz_enabled)
> > + return false;
> > +
> > + /* 3DSTATE_PS_EXTRA::PixelShaderValid */
> > + struct anv_pipeline *pipeline = cmd_buffer->state.pipeline;
> > + if (!anv_pipeline_has_stage(pipeline, MESA_SHADER_FRAGMENT))
> > + return false;
> > +
> > + /* !(3DSTATE_WM::EDSC_Mode == EDSC_PREPS) */
> > + const struct brw_wm_prog_data *wm_prog_data =
> get_wm_prog_data(pipeline);
> > + if (wm_prog_data->early_fragment_tests)
> > + return false;
>
> In keeping with your top-to-bottom evaluation of the logical statement,
> could you move this part to be above the PixelShaderValid part?
>
Not really. If we don't' have a fragment shader, we wm_prog_data is NULL
> > +
> > + /* We never use anv_pipeline for HiZ ops so this is trivially true:
> > + * !(3DSTATE_WM_HZ_OP::DepthBufferClear ||
> ^
> misaligned asterisk
>
Fixed.
> > + * 3DSTATE_WM_HZ_OP::DepthBufferResolve ||
> > + * 3DSTATE_WM_HZ_OP::Hierarchical Depth Buffer Resolve Enable ||
> > + * 3DSTATE_WM_HZ_OP::StencilBufferClear)
> > + */
> > +
> > + /* 3DSTATE_WM_DEPTH_STENCIL::DepthTestEnable */
> > + if (!pipeline->depth_test_enable)
> > + return false;
> > +
> > + /* (((3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > + * 3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > + * 3DSTATE_PS_BLEND::AlphaToCoverageEnable ||
> > + * 3DSTATE_PS_BLEND::AlphaTestEnable ||
> > + * 3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable) &&
> > + * 3DSTATE_WM::ForceKillPix != ForceOff &&
> > + * ((3DSTATE_WM_DEPTH_STENCIL::DepthWriteEnable &&
> > + * 3DSTATE_DEPTH_BUFFER::DEPTH_WRITE_ENABLE) ||
> > + * (3DSTATE_WM_DEPTH_STENCIL::Stencil Buffer Write Enable &&
> > + * 3DSTATE_DEPTH_BUFFER::STENCIL_WRITE_ENABLE &&
> > + * 3DSTATE_STENCIL_BUFFER::STENCIL_BUFFER_ENABLE))) ||
> > + * (3DSTATE_PS_EXTRA:: Pixel Shader Computed Depth mode !=
> PSCDEPTH_OFF))
> > + */
> > + return (pipeline->kill_pixel && (pipeline->writes_depth ||
> > + pipeline->writes_stencil)) ||
>
> anv_pipeline::writes_stencil !=
> (3DSTATE_WM_DEPTH_STENCIL::Stencil Buffer Write Enable &&
> 3DSTATE_DEPTH_BUFFER::STENCIL_WRITE_ENABLE &&
> 3DSTATE_STENCIL_BUFFER::STENCIL_BUFFER_ENABLE);
>
> The last two lines are not accounted for - we don't detect if the
> currently bound depth_stencil attachment lacks or possesses a stencil
> buffer.
>
We should be checking for the presence of a stencil aspect in the
pipeline. I think that got missed when I added the writes_stencil bit. We
do by the end of the series, but I'll patch up the disable stencil writes
patch to make it check.
> This is a valid scenario according to section 25.9. Stencil Test of the
> Vulkan spec, which states:
>
> If there is no stencil framebuffer attachment, stencil modification
> cannot occur, and it is as if the stencil tests always pass.
>
> anv_pipeline::writes_depth should be correct because hiz_enabled is true
> by the time we reach it. For hiz_enabled to be true, there must be a
> depth buffer present.
>
Yup
> > + wm_prog_data->computed_depth_mode != PSCDEPTH_OFF;
> > +}
> > +
> > +void
> > genX(cmd_buffer_flush_dynamic_state)(struct anv_cmd_buffer *cmd_buffer)
> > {
> > struct anv_pipeline *pipeline = cmd_buffer->state.pipeline;
> > @@ -211,6 +340,7 @@ genX(cmd_buffer_flush_dynamic_state)(struct
> anv_cmd_buffer *cmd_buffer)
> > }
> >
> > if (cmd_buffer->state.dirty & (ANV_CMD_DIRTY_PIPELINE |
> > + ANV_CMD_DIRTY_RENDER_TARGETS |
>
> Why is this necessary?
>
We set RENDER_TARGETS dirty when the depth buffer changes due to
NextSubpass or BeginCommandBuffer
> > ANV_CMD_DIRTY_DYNAMIC_STENCIL_COMPARE_MASK
> |
> > ANV_CMD_DIRTY_DYNAMIC_STENCIL_WRITE_MASK))
> {
> > uint32_t wm_depth_stencil_dw[GENX(3DSTATE_WM_DEPTH_STENCIL_
> length)];
> > @@ -234,6 +364,9 @@ genX(cmd_buffer_flush_dynamic_state)(struct
> anv_cmd_buffer *cmd_buffer)
> >
> > anv_batch_emit_merge(&cmd_buffer->batch, wm_depth_stencil_dw,
> > pipeline->gen8.wm_depth_stencil);
> > +
> > + genX(cmd_buffer_enable_pma_fix)(cmd_buffer,
> > + want_depth_pma_fix(cmd_buffer));
> > }
> > #else
> > if (cmd_buffer->state.dirty & ANV_CMD_DIRTY_DYNAMIC_BLEND_CONSTANTS)
> {
> > diff --git a/src/intel/vulkan/genX_blorp_exec.c
> b/src/intel/vulkan/genX_blorp_exec.c
> > index 663e6c9..6f0b063 100644
> > --- a/src/intel/vulkan/genX_blorp_exec.c
> > +++ b/src/intel/vulkan/genX_blorp_exec.c
> > @@ -154,6 +154,11 @@ genX(blorp_exec)(struct blorp_batch *batch,
> >
> > genX(cmd_buffer_emit_gen7_depth_flush)(cmd_buffer);
> >
> > + /* BLORP doesn't do anything fancy with depth such as discards, so
> we want
> > + * the PMA fix off. Also, off is always the safe option.
> > + */
> > + genX(cmd_buffer_enable_pma_fix)(cmd_buffer, false);
> > +
> > blorp_exec(batch, params);
> >
> > cmd_buffer->state.vb_dirty = ~0;
> > diff --git a/src/intel/vulkan/genX_cmd_buffer.c
> b/src/intel/vulkan/genX_cmd_buffer.c
> > index b6b7f74..66de93a 100644
> > --- a/src/intel/vulkan/genX_cmd_buffer.c
> > +++ b/src/intel/vulkan/genX_cmd_buffer.c
> > @@ -627,6 +627,11 @@ genX(EndCommandBuffer)(
> > {
> > ANV_FROM_HANDLE(anv_cmd_buffer, cmd_buffer, commandBuffer);
> >
> > + /* We want every command buffer to start with the PMA fix in a known
> state,
> > + * so we disable it at the end of the command buffer.
> > + */
> > + genX(cmd_buffer_enable_pma_fix)(cmd_buffer, false);
> > +
> > genX(cmd_buffer_apply_pipe_flushes)(cmd_buffer);
> >
> > anv_cmd_buffer_end_batch_buffer(cmd_buffer);
> > @@ -644,6 +649,11 @@ genX(CmdExecuteCommands)(
> >
> > assert(primary->level == VK_COMMAND_BUFFER_LEVEL_PRIMARY);
> >
> > + /* The secondary command buffers will assume that the PMA fix is
> disabled
> > + * when they begin executing. Make sure this is true.
> > + */
> > + genX(cmd_buffer_enable_pma_fix)(primary, false);
> > +
> > for (uint32_t i = 0; i < commandBufferCount; i++) {
> > ANV_FROM_HANDLE(anv_cmd_buffer, secondary, pCmdBuffers[i]);
> >
> > @@ -2181,7 +2191,8 @@ cmd_buffer_emit_depth_stencil(struct
> anv_cmd_buffer *cmd_buffer)
> > const bool has_stencil =
> > image && (image->aspects & VK_IMAGE_ASPECT_STENCIL_BIT);
> >
> > - /* FIXME: Implement the PMA stall W/A */
> > + cmd_buffer->state.hiz_enabled = has_hiz;
> > +
> > /* FIXME: Width and Height are wrong */
> >
> > genX(cmd_buffer_emit_gen7_depth_flush)(cmd_buffer);
> > @@ -2419,6 +2430,8 @@ void genX(CmdEndRenderPass)(
> >
> > anv_cmd_buffer_resolve_subpass(cmd_buffer);
> >
> > + cmd_buffer->state.hiz_enabled = false;
> > +
> > #ifndef NDEBUG
> > anv_dump_add_framebuffer(cmd_buffer, cmd_buffer->state.framebuffer);
> > #endif
> > diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_
> pipeline.c
> > index 18fe48c..0588d01 100644
> > --- a/src/intel/vulkan/genX_pipeline.c
> > +++ b/src/intel/vulkan/genX_pipeline.c
> > @@ -653,6 +653,8 @@ emit_ds_state(struct anv_pipeline *pipeline,
> > * to make sure it's initialized to something useful.
> > */
> > pipeline->writes_stencil = false;
> > + pipeline->writes_depth = false;
> > + pipeline->depth_test_enable = false;
> > memset(depth_stencil_dw, 0, sizeof(depth_stencil_dw));
> > return;
> > }
> > @@ -711,6 +713,9 @@ emit_ds_state(struct anv_pipeline *pipeline,
> > if (info->depthTestEnable && info->depthCompareOp ==
> VK_COMPARE_OP_EQUAL)
> > depth_stencil.DepthBufferWriteEnable = false;
> >
> > + pipeline->writes_depth = depth_stencil.DepthBufferWriteEnable;
> > + pipeline->depth_test_enable = depth_stencil.DepthTestEnable;
> > +
> > #if GEN_GEN <= 7
> > GENX(DEPTH_STENCIL_STATE_pack)(NULL, depth_stencil_dw,
> &depth_stencil);
> > #else
> > @@ -1429,6 +1434,38 @@ emit_3dstate_vf_topology(struct anv_pipeline
> *pipeline)
> > }
> > #endif
> >
> > +static void
> > +compute_kill_pixel(struct anv_pipeline *pipeline,
> > + const VkPipelineMultisampleStateCreateInfo *ms_info,
> > + const struct anv_subpass *subpass)
> > +{
> > + if (!anv_pipeline_has_stage(pipeline, MESA_SHADER_FRAGMENT)) {
> > + pipeline->kill_pixel = false;
> > + return;
> > + }
> > +
> > + const struct brw_wm_prog_data *wm_prog_data =
> get_wm_prog_data(pipeline);
> > +
> > + /* This computes the KillPixel portion of the computation for
> whether or
> > + * not we want to enable the PMA fix on gen8. It's given by this
> chunk of
> > + * the giant formula:
> > + *
> > + * (3DSTATE_PS_EXTRA::PixelShaderKillsPixels ||
> > + * 3DSTATE_PS_EXTRA::oMask Present to RenderTarget ||
> > + * 3DSTATE_PS_BLEND::AlphaToCoverageEnable ||
> > + * 3DSTATE_PS_BLEND::AlphaTestEnable ||
> > + * 3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable)
> > + *
> > + * 3DSTATE_WM_CHROMAKEY::ChromaKeyKillEnable is always false and so
> is
> > + * 3DSTATE_PS_BLEND::AlphaTestEnable since Vulkan doesn't have a
> concept
> > + * of an alpha test.
> > + */
> > + pipeline->kill_pixel =
> > + subpass->has_ds_self_dep || wm_prog_data->uses_kill ||
>
> Why do we set kill_pixel in the presence of has_ds_self_dep?
>
> Section 7.1 of the Vulkan spec states:
>
> If a subpass uses the same attachment as both an input attachment and
> either a color attachment or a depth/stencil attachment, writes via
> the color or depth/stencil attachment are not automatically made
> visible to reads via the input attachment, causing a feedback loop,
> except in any of the following conditions:
>
> [...]
>
> I don't see how any of the conditions are satisfied through the use
> of kill_pixel.
>
There's a really good comment where we set
3DSTATE_PS::PixelShaderKillsPixel and
3DSTATE_PS_EXTRA::PixelShaderKillsPixel
> > + wm_prog_data->uses_omask ||
> > + (ms_info && ms_info->alphaToCoverageEnable);
> > +}
> > +
> > static VkResult
> > genX(graphics_pipeline_create)(
> > VkDevice _device,
> > @@ -1466,6 +1503,7 @@ genX(graphics_pipeline_create)(
> > emit_ds_state(pipeline, pCreateInfo->pDepthStencilState, pass,
> subpass);
> > emit_cb_state(pipeline, pCreateInfo->pColorBlendState,
> > pCreateInfo->pMultisampleState);
> > + compute_kill_pixel(pipeline, pCreateInfo->pMultisampleState,
> subpass);
> >
> > emit_urb_setup(pipeline);
> >
> > --
> > 2.5.0.400.gff86faf
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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