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drm/xe: Drop unnecessary STOP_RING clearing

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The STOP_RING bit in MI_MODE is already clear by default out of hardware
reset and will only be '1' if the driver intentionally sets it after
that.

The logic of clearing this bit appears to originate from very
early (pre-GuC, pre-execlist) code in i915 where we needed to stop the
ring before performing a host-initiated engine reset; after the reset
the STOP_RING bit needed to be cleared to allow execution to resume.

None of that is relevant to Xe (or even modern i915) since STOP_RING
isn't necessary for execlist-based engine resets (and even if it were,
Xe doesn't initiate any engine resets; the GuC handles that now).

Bspec: 60356, 60184
Reviewed-by: Shuicheng Lin <shuicheng.lin@intel.com>
Link: https://patch.msgid.link/20260424-engine-setup-v2-8-59cc620a25f1@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
This commit is contained in:
Matt Roper 2026-04-24 13:48:18 -07:00
parent 4c936a0a22
commit 461a6698d6
3 changed files with 0 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/gpu/drm/xe/regs/xe_engine_regs.h
View File

@ -176,7 +176,6 @@
#define RING_TIMESTAMP_UDW(base) XE_REG((base) + 0x358 + 4)
#define RING_VALID_MASK 0x00000001
#define RING_VALID 0x00000001
#define STOP_RING REG_BIT(8)
#define RING_CTX_TIMESTAMP(base) XE_REG((base) + 0x3a8)
#define RING_CTX_TIMESTAMP_UDW(base) XE_REG((base) + 0x3ac)

3
drivers/gpu/drm/xe/xe_hw_engine.c
View File

@ -327,9 +327,6 @@ void xe_hw_engine_enable_ring(struct xe_hw_engine *hwe)
{
xe_hw_engine_mmio_write32(hwe, RING_HWS_PGA(0),
xe_bo_ggtt_addr(hwe->hwsp));
xe_hw_engine_mmio_write32(hwe, RING_MI_MODE(0),
REG_MASKED_FIELD_DISABLE(STOP_RING));
xe_hw_engine_mmio_read32(hwe, RING_MI_MODE(0));
}
static bool xe_hw_engine_match_fixed_cslice_mode(const struct xe_device *xe,

20
drivers/gpu/drm/xe/xe_lrc.c
View File

@ -682,25 +682,6 @@ static void set_memory_based_intr(u32 *regs, struct xe_hw_engine *hwe)
}
}
static int lrc_ring_mi_mode(struct xe_hw_engine *hwe)
{
struct xe_device *xe = gt_to_xe(hwe->gt);
if (GRAPHICS_VERx100(xe) >= 1250)
return 0x70;
else
return 0x60;
}
static void reset_stop_ring(u32 *regs, struct xe_hw_engine *hwe)
{
int x;
x = lrc_ring_mi_mode(hwe);
regs[x + 1] &= ~STOP_RING;
regs[x + 1] |= STOP_RING << 16;
}
static inline bool xe_lrc_has_indirect_ring_state(struct xe_lrc *lrc)
{
return lrc->flags & XE_LRC_FLAG_INDIRECT_RING_STATE;
@ -980,7 +961,6 @@ static void *empty_lrc_data(struct xe_hw_engine *hwe)
set_offsets(regs, reg_offsets(gt_to_xe(gt), hwe->class), hwe);
set_context_control(regs, hwe);
set_memory_based_intr(regs, hwe);
reset_stop_ring(regs, hwe);
if (xe_gt_has_indirect_ring_state(gt)) {
regs = data + xe_gt_lrc_size(gt, hwe->class) -
LRC_INDIRECT_RING_STATE_SIZE;