From patchwork Thu Jun 7 07:30:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10451269 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C427B6037F for ; Thu, 7 Jun 2018 07:30:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B025A2983D for ; Thu, 7 Jun 2018 07:30:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A483029952; Thu, 7 Jun 2018 07:30:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 525572983D for ; Thu, 7 Jun 2018 07:30:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 351DD6F186; Thu, 7 Jun 2018 07:30:39 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 650B26F184 for ; Thu, 7 Jun 2018 07:30:38 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 11968805-1500050 for multiple; Thu, 07 Jun 2018 08:30:29 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Thu, 07 Jun 2018 08:30:28 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Thu, 7 Jun 2018 08:30:25 +0100 Message-Id: <20180607073025.21066-2-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180607073025.21066-1-chris@chris-wilson.co.uk> References: <20180607073025.21066-1-chris@chris-wilson.co.uk> X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH 2/2] drm/i915/ringbuffer: Brute force context restore X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP An issue encountered with switching mm on gen7 is that the GPU likes to hang (with the VS unit busy) when told to force restore the current context. We can simply workaround this by substituting the MI_FORCE_RESTORE flag with a round-trip through the kernel_context, forcing the context to be saved and restored; thereby reloading the PP_DIR registers and updating the modified page directory! Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: Mika Kuoppala Cc: Matthew Auld --- drivers/gpu/drm/i915/intel_ringbuffer.c | 30 ++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 4051fb55a2cf..9e6883606b1f 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -1459,6 +1459,7 @@ static inline int mi_set_context(struct i915_request *rq, u32 flags) (HAS_LEGACY_SEMAPHORES(i915) && IS_GEN7(i915)) ? INTEL_INFO(i915)->num_rings - 1 : 0; + bool force_restore = false; int len; u32 *cs; @@ -1472,6 +1473,12 @@ static inline int mi_set_context(struct i915_request *rq, u32 flags) len = 4; if (IS_GEN7(i915)) len += 2 + (num_rings ? 4*num_rings + 6 : 0); + if (flags & MI_FORCE_RESTORE) { + GEM_BUG_ON(flags & MI_RESTORE_INHIBIT); + flags &= ~MI_FORCE_RESTORE; + force_restore = true; + len += 2; + } cs = intel_ring_begin(rq, len); if (IS_ERR(cs)) @@ -1497,6 +1504,20 @@ static inline int mi_set_context(struct i915_request *rq, u32 flags) } *cs++ = MI_NOOP; + if (force_restore) { + /* + * The HW doesn't handle being told to restore the current + * context very well. Quite often it likes goes to go off and + * sulk, especially when it is meant to be reloading PP_DIR. + * A very simple fix to force the reload is to simply switch + * away from the current context and back again. + */ + *cs++ = MI_SET_CONTEXT; + *cs++ = i915_ggtt_offset(to_intel_context(i915->kernel_context, + engine)->state) | + MI_MM_SPACE_GTT | + MI_RESTORE_INHIBIT; + } *cs++ = MI_SET_CONTEXT; *cs++ = i915_ggtt_offset(rq->hw_context->state) | flags; /* @@ -1586,11 +1607,14 @@ static int switch_context(struct i915_request *rq) to_mm->pd_dirty_rings &= ~intel_engine_flag(engine); engine->legacy_active_ppgtt = to_mm; - hw_flags = MI_FORCE_RESTORE; + + if (to_ctx == from_ctx) { + hw_flags = MI_FORCE_RESTORE; + from_ctx = NULL; + } } - if (rq->hw_context->state && - (to_ctx != from_ctx || hw_flags & MI_FORCE_RESTORE)) { + if (rq->hw_context->state && to_ctx != from_ctx) { GEM_BUG_ON(engine->id != RCS); /*