Commit 0fa9e6d7 authored by Sergii Romantsov's avatar Sergii Romantsov Committed by Jason Ekstrand
Browse files

anv/skylake: disable ForceThreadDispatchEnable

On Skylake enabling of ForceThreadDispatchEnable causes gpu-hang.

-v2: enabling of  ForceThreadDispatchEnable is only for gen8, for
     gen9 and higher reverted enabling of PixelShaderHasUAV.

-v3 (Jason Ekstrand): Rework the comments a bit.

CC: Jason Ekstrand <jason.ekstrand@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107941
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107760


Fixes: 79270d2140ec (anv: Stop setting 3DSTATE_PS_EXTRA::PixelShaderHasUAV)
Signed-off-by: default avatarSergii Romantsov <sergii.romantsov@globallogic.com>
Reviewed-by: default avatarJason Ekstrand <jason@jlekstrand.net>
parent 322a919a
......@@ -1445,12 +1445,12 @@ emit_3dstate_wm(struct anv_pipeline *pipeline, struct anv_subpass *subpass,
wm.EarlyDepthStencilControl = EDSC_NORMAL;
}
#if GEN_GEN >= 8
/* Gen8 hardware tries to compute ThreadDispatchEnable for us but
* doesn't take into account KillPixels when no depth or stencil
* writes are enabled. In order for occlusion queries to work
* correctly with no attachments, we need to force-enable PS thread
* dispatch.
#if GEN_GEN == 8
/* Gen8 and later hardware tries to compute ThreadDispatchEnable for
* us but doesn't take into account KillPixels when no depth or
* stencil writes are enabled. In order for occlusion queries to
* work correctly with no attachments, we need to force-enable PS
* thread dispatch.
*
* The BDW docs are pretty clear that that this bit isn't validated
* and probably shouldn't be used in production:
......@@ -1460,7 +1460,9 @@ emit_3dstate_wm(struct anv_pipeline *pipeline, struct anv_subpass *subpass,
*
* Unfortunately, however, the other mechanism we have for doing this
* is 3DSTATE_PS_EXTRA::PixelShaderHasUAV which causes hangs on BDW.
* Given two bad options, we choose the one which works.
* Given two bad options, we choose the one which works. On Skylake
* and later, setting ForceThreadDispatchEnable causes GPU hangs so
* we use the PixelShaderHasUAV mechanism there.
*/
if ((wm_prog_data->has_side_effects || wm_prog_data->uses_kill) &&
!has_color_buffer_write_enabled(pipeline, blend))
......@@ -1663,6 +1665,32 @@ emit_3dstate_ps_extra(struct anv_pipeline *pipeline,
wm_prog_data->uses_kill;
#if GEN_GEN >= 9
/* Gen8 and later hardware tries to compute ThreadDispatchEnable for us
* but doesn't take into account KillPixels when no depth or stencil
* writes are enabled. In order for occlusion queries to work correctly
* with no attachments, we need to force-enable PS thread dispatch.
*
* The stricter cross-primitive coherency guarantees that the hardware
* gives us with the "Accesses UAV" bit set for at least one shader stage
* and the "UAV coherency required" bit set on the 3DPRIMITIVE command are
* redundant within the current image, atomic counter and SSBO GL and
* Vulkan APIs, which all have very loose ordering and coherency
* requirements and generally rely on the application to insert explicit
* barriers when a shader invocation is expected to see the memory
* writes performed by the invocations of some previous primitive.
* Regardless of the value of "UAV coherency required", the "Accesses
* UAV" bits will implicitly cause an in most cases useless DC flush
* when the lowermost stage with the bit set finishes execution.
*
* Unfortunately, however, the other mechanism we have for doing this is
* 3DSTATE_WM::ForceThreadDispatchEnable which causes GPU hangs on
* Skylake and later hardware. On Broadwell, however, setting this bit
* causes GPU hangs so we use ForceThreadDispatchEnable there.
*/
if ((wm_prog_data->has_side_effects || wm_prog_data->uses_kill) &&
!has_color_buffer_write_enabled(pipeline, blend))
ps.PixelShaderHasUAV = true;
ps.PixelShaderComputesStencil = wm_prog_data->computed_stencil;
ps.PixelShaderPullsBary = wm_prog_data->pulls_bary;
......
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