From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932065AbbHEVuR (ORCPT ); Wed, 5 Aug 2015 17:50:17 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38415 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754351AbbHEVuF (ORCPT ); Wed, 5 Aug 2015 17:50:05 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Chris Wilson , Daniel Vetter , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 027/107] drm/i915: Declare the swizzling unknown for L-shaped configurations Date: Wed, 5 Aug 2015 14:48:19 -0700 Message-Id: <1438811379-384-28-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438811379-384-1-git-send-email-kamal@canonical.com> References: <1438811379-384-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson commit 19ee835cdb0b5a8eb11a68f25a51b8039d564488 upstream. The old style of memory interleaving swizzled upto the end of the first even bank of memory, and then used the remainder as unswizzled on the unpaired bank - i.e. swizzling is not constant for all memory. This causes problems when we try to migrate memory and so the kernel prevents migration at all when we detect L-shaped inconsistent swizzling. However, this issue also extends to userspace who try to manually detile into memory as the swizzling for an individual page is unknown (it depends on its physical address only known to the kernel), userspace cannot correctly swizzle objects. v2: Mark the global swizzling as unknown rather than adjust the value reported to userspace. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91105 Signed-off-by: Chris Wilson Cc: Daniel Vetter Signed-off-by: Daniel Vetter Signed-off-by: Kamal Mostafa --- drivers/gpu/drm/i915/i915_gem_tiling.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c index ffe9072..8ce8c5e 100644 --- a/drivers/gpu/drm/i915/i915_gem_tiling.c +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c @@ -183,8 +183,18 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev) if (IS_GEN4(dev)) { uint32_t ddc2 = I915_READ(DCC2); - if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE)) + if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE)) { + /* Since the swizzling may vary within an + * object, we have no idea what the swizzling + * is for any page in particular. Thus we + * cannot migrate tiled pages using the GPU, + * nor can we tell userspace what the exact + * swizzling is for any object. + */ dev_priv->quirks |= QUIRK_PIN_SWIZZLED_PAGES; + swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN; + swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN; + } } if (dcc == 0xffffffff) { -- 1.9.1