From: Matt Roper matthew.d.roper@intel.com
[ Upstream commit 1d734a3e5d6bb266f52eaf2b1400c5d3f1875a54 ]
Early in the development of Xe we identified an issue with SVG state handling on DG2 and MTL (and later on Xe2 as well). In commit 72ac304769dd ("drm/xe: Emit SVG state on RCS during driver load on DG2 and MTL") and commit fb24b858a20d ("drm/xe/xe2: Update SVG state handling") we implemented our own workaround to prevent SVG state from leaking from context A to context B in cases where context B never issues a specific state setting.
The hardware teams have now created official workaround Wa_14019789679 to cover this issue. The workaround description only requires emitting 3DSTATE_MESH_CONTROL, since they believe that's the only SVG instruction that would potentially remain unset by a context B, but still cause notable issues if unwanted values were inherited from context A. However since we already have a more extensive implementation that emits the entire SVG state and prevents _any_ SVG state from unintentionally leaking, we'll stick with our existing implementation just to be safe.
Signed-off-by: Matt Roper matthew.d.roper@intel.com Reviewed-by: Jonathan Cavitt jonathan.cavitt@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20240812181042.2013508-2-matth... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/xe/xe_lrc.c | 35 +++++++++++++++++++++--------- drivers/gpu/drm/xe/xe_wa_oob.rules | 2 ++ 2 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c index 58121821f0814..974a9cd8c3795 100644 --- a/drivers/gpu/drm/xe/xe_lrc.c +++ b/drivers/gpu/drm/xe/xe_lrc.c @@ -5,6 +5,8 @@
#include "xe_lrc.h"
+#include <generated/xe_wa_oob.h> + #include <linux/ascii85.h>
#include "instructions/xe_mi_commands.h" @@ -24,6 +26,7 @@ #include "xe_memirq.h" #include "xe_sriov.h" #include "xe_vm.h" +#include "xe_wa.h"
#define LRC_VALID BIT_ULL(0) #define LRC_PRIVILEGE BIT_ULL(8) @@ -1581,19 +1584,31 @@ void xe_lrc_emit_hwe_state_instructions(struct xe_exec_queue *q, struct xe_bb *b int state_table_size = 0;
/* - * At the moment we only need to emit non-register state for the RCS - * engine. + * Wa_14019789679 + * + * If the driver doesn't explicitly emit the SVG instructions while + * setting up the default LRC, the context switch will write 0's + * (noops) into the LRC memory rather than the expected instruction + * headers. Application contexts start out as a copy of the default + * LRC, and if they also do not emit specific settings for some SVG + * state, then on context restore they'll unintentionally inherit + * whatever state setting the previous context had programmed into the + * hardware (i.e., the lack of a 3DSTATE_* instruction in the LRC will + * prevent the hardware from resetting that state back to any specific + * value). + * + * The official workaround only requires emitting 3DSTATE_MESH_CONTROL + * since that's a specific state setting that can easily cause GPU + * hangs if unintentionally inherited. However to be safe we'll + * continue to emit all of the SVG state since it's best not to leak + * any of the state between contexts, even if that leakage is harmless. */ - if (q->hwe->class != XE_ENGINE_CLASS_RENDER) - return; - - switch (GRAPHICS_VERx100(xe)) { - case 1255: - case 1270 ... 2004: + if (XE_WA(gt, 14019789679) && q->hwe->class == XE_ENGINE_CLASS_RENDER) { state_table = xe_hpg_svg_state; state_table_size = ARRAY_SIZE(xe_hpg_svg_state); - break; - default: + } + + if (!state_table) { xe_gt_dbg(gt, "No non-register state to emit on graphics ver %d.%02d\n", GRAPHICS_VER(xe), GRAPHICS_VERx100(xe) % 100); return; diff --git a/drivers/gpu/drm/xe/xe_wa_oob.rules b/drivers/gpu/drm/xe/xe_wa_oob.rules index 08f7336881e32..d4c33dbc14c7a 100644 --- a/drivers/gpu/drm/xe/xe_wa_oob.rules +++ b/drivers/gpu/drm/xe/xe_wa_oob.rules @@ -30,3 +30,5 @@ 22019338487 MEDIA_VERSION(2000) GRAPHICS_VERSION(2001) 16023588340 GRAPHICS_VERSION(2001) +14019789679 GRAPHICS_VERSION(1255) + GRAPHICS_VERSION_RANGE(1270, 2004)