From patchwork Thu Jun 7 09:57:58 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10451551 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 1ED5060375 for ; Thu, 7 Jun 2018 09:59:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1018E295CE for ; Thu, 7 Jun 2018 09:59:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 050E629B65; Thu, 7 Jun 2018 09:59:15 +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 AA829295CE for ; Thu, 7 Jun 2018 09:59:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DA5CA6F1F0; Thu, 7 Jun 2018 09:59:13 +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 8F8836F1E6 for ; Thu, 7 Jun 2018 09:59:11 +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 11970948-1500050 for multiple; Thu, 07 Jun 2018 10:58:25 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Thu, 07 Jun 2018 10:58:23 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Thu, 7 Jun 2018 10:57:58 +0100 Message-Id: <20180607095815.10938-4-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180607095815.10938-1-chris@chris-wilson.co.uk> References: <20180607095815.10938-1-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 03/20] 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 917ca1552600..3df802cc3710 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -1458,6 +1458,7 @@ 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; @@ -1471,6 +1472,12 @@ 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)) @@ -1496,6 +1503,20 @@ 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; /* @@ -1585,11 +1606,14 @@ 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); /*