From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Kuoppala Subject: Re: [PATCH 1/2] drm/i915/execlists: Wrap tail pointer after reset tweaking Date: Mon, 27 Mar 2017 13:44:00 +0300 Message-ID: <87fuhzxamn.fsf@gaia.fi.intel.com> References: <20170327032815.19504-1-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id A42FA8977A for ; Mon, 27 Mar 2017 10:44:54 +0000 (UTC) In-Reply-To: <20170327032815.19504-1-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Chris Wilson , intel-gfx@lists.freedesktop.org Cc: "# v4 . 10+" List-Id: intel-gfx@lists.freedesktop.org Q2hyaXMgV2lsc29uIDxjaHJpc0BjaHJpcy13aWxzb24uY28udWs+IHdyaXRlczoKCj4gSWYgdGhl IHJlcXVlc3QtPndhX3RhaWwgaXMgMCAoYmVjYXVzZSBpdCBsYW5kZWQgZXhhY3RseSBvbiB0aGUg ZW5kIG9mCj4gdGhlIHJpbmdidWZmZXIpLCB3aGVuIHdlIHJlY29uc3RydWN0IHJlcXVlc3QtPnRh aWwgZm9sbG93aW5nIGEgcmVzZXQgd2UKPiBmaWxsIGluIGFuIGlsbGVnYWwgdmFsdWUgKC04IG9y IDB4MDAxZmZmZjgpLiBBcyBhIHJlc3VsdCwgUklOR19IRUFEIGlzCj4gbmV2ZXIgYWJsZSB0byBj YXRjaCB1cCB3aXRoIFJJTkdfVEFJTCBhbmQgdGhlIEdQVSBzcGlucyBlbmRsZXNzbHkuIElmCj4g dGhlIHJpbmcgY29udGFpbnMgYSBjb3VwbGUgb2YgYnJlYWRjcnVtYnMsIGV2ZW4gb3VyIGhhbmdj aGVjayBpcyB1bmFibGUKPiB0byBjYXRjaCB0aGUgYnVzeS1sb29waW5nIGFzIHRoZSBBQ1RIRCBh bmQgc2Vxbm8gY29udGludWFsbHkgYWR2YW5jZS4KClRhaWwgaXMgcGFzdCByaW5nIHNpemUgKG9u IGh3KSBhbmQgdGhlIHJpbmcgY29udGVudHMgaGFzIHNlcW5vIHdyaXRlcy4KU28gd2Ugd2lsbCBy ZXBsYXkgdGhlIHJpbmcgY29udGVudHMgb3ZlciBhbmQgb3ZlciBhbmQgc2Vxbm8gYWR2YW5jZXMK YW5kIHdyYXBzIGJhY2sgdG8gdGhlIGZpcnN0IGJyZWFkY3J1bWJzIGluIHJpbmc/Cgo+IEZpeGVz OiBhM2FhYmU4NmEzNDAgKCJkcm0vaTkxNS9leGVjbGlzdHM6IFJlaW5pdGlhbGlzZSBjb250ZXh0 IGltYWdlIGFmdGVyIEdQVSBoYW5nIikKPiBTaWduZWQtb2ZmLWJ5OiBDaHJpcyBXaWxzb24gPGNo cmlzQGNocmlzLXdpbHNvbi5jby51az4KPiBDYzogTWlrYSBLdW9wcGFsYSA8bWlrYS5rdW9wcGFs YUBpbnRlbC5jb20+Cj4gQ2M6IDxzdGFibGVAdmdlci5rZXJuZWwub3JnPiAjIHY0LjEwKwo+IC0t LQo+ICBkcml2ZXJzL2dwdS9kcm0vaTkxNS9pbnRlbF9scmMuYyB8IDEgKwo+ICAxIGZpbGUgY2hh bmdlZCwgMSBpbnNlcnRpb24oKykKPgo+IGRpZmYgLS1naXQgYS9kcml2ZXJzL2dwdS9kcm0vaTkx NS9pbnRlbF9scmMuYyBiL2RyaXZlcnMvZ3B1L2RybS9pOTE1L2ludGVsX2xyYy5jCj4gaW5kZXgg M2ZkYWJiYTBhMzJkLi5jOGRkODQ4ZDJlYmUgMTAwNjQ0Cj4gLS0tIGEvZHJpdmVycy9ncHUvZHJt L2k5MTUvaW50ZWxfbHJjLmMKPiArKysgYi9kcml2ZXJzL2dwdS9kcm0vaTkxNS9pbnRlbF9scmMu Ywo+IEBAIC0xMzAyLDYgKzEzMDIsNyBAQCBzdGF0aWMgdm9pZCByZXNldF9jb21tb25fcmluZyhz dHJ1Y3QgaW50ZWxfZW5naW5lX2NzICplbmdpbmUsCj4gIAo+ICAJLyogUmVzZXQgV2FJZGxlTGl0 ZVJlc3RvcmU6YmR3LHNrbCBhcyB3ZWxsICovCj4gIAlyZXF1ZXN0LT50YWlsID0gcmVxdWVzdC0+ d2FfdGFpbCAtIFdBX1RBSUxfRFdPUkRTICogc2l6ZW9mKHUzMik7Cj4gKwlyZXF1ZXN0LT50YWls ICY9IHJlcXVlc3QtPnJpbmctPnNpemUgLSAxOwo+ICAJR0VNX0JVR19PTighSVNfQUxJR05FRChy ZXF1ZXN0LT50YWlsLCA4KSk7Cj4gIH0KPiAgCj4gLS0gCj4gMi4xMS4wCj4KPiBfX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwo+IEludGVsLWdmeCBtYWlsaW5n IGxpc3QKPiBJbnRlbC1nZnhAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCj4gaHR0cHM6Ly9saXN0cy5m cmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9pbnRlbC1nZngKX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KSW50ZWwtZ2Z4IG1haWxpbmcgbGlzdApJ bnRlbC1nZnhAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Au b3JnL21haWxtYW4vbGlzdGluZm8vaW50ZWwtZ2Z4Cg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com ([192.55.52.43]:3571 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752086AbdC0KpO (ORCPT ); Mon, 27 Mar 2017 06:45:14 -0400 From: Mika Kuoppala To: Chris Wilson , intel-gfx@lists.freedesktop.org Cc: "# v4 . 10+" Subject: Re: [Intel-gfx] [PATCH 1/2] drm/i915/execlists: Wrap tail pointer after reset tweaking In-Reply-To: <20170327032815.19504-1-chris@chris-wilson.co.uk> References: <20170327032815.19504-1-chris@chris-wilson.co.uk> Date: Mon, 27 Mar 2017 13:44:00 +0300 Message-ID: <87fuhzxamn.fsf@gaia.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: stable-owner@vger.kernel.org List-ID: Chris Wilson writes: > If the request->wa_tail is 0 (because it landed exactly on the end of > the ringbuffer), when we reconstruct request->tail following a reset we > fill in an illegal value (-8 or 0x001ffff8). As a result, RING_HEAD is > never able to catch up with RING_TAIL and the GPU spins endlessly. If > the ring contains a couple of breadcrumbs, even our hangcheck is unable > to catch the busy-looping as the ACTHD and seqno continually advance. Tail is past ring size (on hw) and the ring contents has seqno writes. So we will replay the ring contents over and over and seqno advances and wraps back to the first breadcrumbs in ring? > Fixes: a3aabe86a340 ("drm/i915/execlists: Reinitialise context image after GPU hang") > Signed-off-by: Chris Wilson > Cc: Mika Kuoppala > Cc: # v4.10+ > --- > drivers/gpu/drm/i915/intel_lrc.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c > index 3fdabba0a32d..c8dd848d2ebe 100644 > --- a/drivers/gpu/drm/i915/intel_lrc.c > +++ b/drivers/gpu/drm/i915/intel_lrc.c > @@ -1302,6 +1302,7 @@ static void reset_common_ring(struct intel_engine_cs *engine, > > /* Reset WaIdleLiteRestore:bdw,skl as well */ > request->tail = request->wa_tail - WA_TAIL_DWORDS * sizeof(u32); > + request->tail &= request->ring->size - 1; > GEM_BUG_ON(!IS_ALIGNED(request->tail, 8)); > } > > -- > 2.11.0 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx