[PATCH 1/2] drm/i915/lrc: Clear context restore/save inhibit flags for new contexts

From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Subject: [PATCH 1/2] drm/i915/lrc: Clear context restore/save inhibit flags for new contexts
Date: Thu, 25 Jan 2018 11:24:42 +0000	[thread overview]
Message-ID: <20180125112443.12745-1-chris@chris-wilson.co.uk> (raw)

CTX_CONTEXT_CONTROL (CTX_SR_CTL) operates as a masked register and so
will only apply the bits that are selected by the upper half. In the
case of selectively enabling sr inhibit, this may mean the context keeps
the current setting (so forgetting to save the context later, eventually
leading to a very upset GPU!).

Fixes: d2b4b97933f5 ("drm/i915: Record the default hw state after reset upon load")
Fixes: 517aaffe0c1b ("drm/i915/execlists: Inhibit context save/restore for the fake preempt context")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 89e92defbcfe..29b14d7d4b07 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -456,6 +456,12 @@ static void inject_preempt_context(struct intel_engine_cs *engine)
 	ce->ring->tail &= (ce->ring->size - 1);
 	ce->lrc_reg_state[CTX_RING_TAIL+1] = ce->ring->tail;
 
+	GEM_BUG_ON((ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1] &
+		    _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
+				       CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)) !=
+		   _MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
+				      CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT));
+
 	GEM_TRACE("%s\n", engine->name);
 	for (n = execlists_num_ports(&engine->execlists); --n; )
 		elsp_write(0, engine->execlists.elsp);
@@ -2118,6 +2124,8 @@ static void execlists_init_reg_state(u32 *regs,
 				 MI_LRI_FORCE_POSTED;
 
 	CTX_REG(regs, CTX_CONTEXT_CONTROL, RING_CONTEXT_CONTROL(engine),
+		_MASKED_BIT_DISABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
+				    CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT) |
 		_MASKED_BIT_ENABLE(CTX_CTRL_INHIBIT_SYN_CTX_SWITCH |
 				   (HAS_RESOURCE_STREAMER(dev_priv) ?
 				   CTX_CTRL_RS_CTX_ENABLE : 0)));
-- 
2.15.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
