From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 36259EB1053 for ; Tue, 10 Mar 2026 11:57:45 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1A7EC10E6C1; Tue, 10 Mar 2026 11:57:33 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=lankhorst.se header.i=@lankhorst.se header.b="nboErVO8"; dkim-atps=neutral Received: from lankhorst.se (unknown [141.105.120.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2336810E6B1; Tue, 10 Mar 2026 11:57:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lankhorst.se; s=default; t=1773143849; bh=HLG5zYzTknv1yxOwIFjibEQ+6aTsE3QuUrk4TOZ8nV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nboErVO8vwtRG7Y3yiLluwZgRD0288DsJh5mChUmHSJY6D/Jsm/29OQJ0W49qWQ6u byOn12Pa/w5Kprvoney5bF8SBmnwEek05Mqg4IcFKMCIF463xV8e2CFi1jJ1cK497/ BH/kMThqeNJnxVsTA3GQUCLxqWlTnM3zpFJoErK/nnYBnh5ar2zorhVCLb+KfmbN4d HKJcFC9nLQNFrb0+T0pYo6bHjXJa5dCbP+4CvxAU+d634BV4wxKyRmIwx4s+xOo32p kJznHqK+DgSgKG6LnIid9T1rqvM6EsS7HH6vC2952vUYqyrsAC71NmP7sMg5rN9YLI A/V2Xx1CxhTZg== From: Maarten Lankhorst To: intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org, Maarten Lankhorst Subject: [PATCH v7 10/26] drm/i915/display: Do not take uncore lock in i915_get_vblank_counter Date: Tue, 10 Mar 2026 12:56:52 +0100 Message-ID: <20260310115709.2276203-11-dev@lankhorst.se> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260310115709.2276203-1-dev@lankhorst.se> References: <20260310115709.2276203-1-dev@lankhorst.se> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This fixes a lockdep splat that occurs in the code that should be run with interrupts disabled. The uncore lock should not be taken and released repeatedly in a timing sensitive path. Signed-off-by: Maarten Lankhorst --- drivers/gpu/drm/i915/display/intel_de.h | 8 ++++++ drivers/gpu/drm/i915/display/intel_vblank.c | 4 +-- drivers/gpu/drm/i915/intel_uncore.h | 26 +++++++++++++------ .../drm/xe/compat-i915-headers/intel_uncore.h | 7 +++++ 4 files changed, 35 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_de.h b/drivers/gpu/drm/i915/display/intel_de.h index f30f3f8ebee1d..8990c2c778efe 100644 --- a/drivers/gpu/drm/i915/display/intel_de.h +++ b/drivers/gpu/drm/i915/display/intel_de.h @@ -68,6 +68,14 @@ intel_de_read64_2x32(struct intel_display *display, return val; } +static inline u64 +intel_de_read64_2x32_fw(struct intel_display *display, + i915_reg_t lower_reg, i915_reg_t upper_reg) +{ + return intel_uncore_read64_2x32_fw(__to_uncore(display), + lower_reg, upper_reg); +} + static inline void intel_de_posting_read(struct intel_display *display, i915_reg_t reg) { diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c index e204c260b9aef..749127ae7794c 100644 --- a/drivers/gpu/drm/i915/display/intel_vblank.c +++ b/drivers/gpu/drm/i915/display/intel_vblank.c @@ -109,8 +109,8 @@ u32 i915_get_vblank_counter(struct drm_crtc *crtc) * we get a low value that's stable across two reads of the high * register. */ - frame = intel_de_read64_2x32(display, PIPEFRAMEPIXEL(display, pipe), - PIPEFRAME(display, pipe)); + frame = intel_de_read64_2x32_fw(display, PIPEFRAMEPIXEL(display, pipe), + PIPEFRAME(display, pipe)); pixel = frame & PIPE_PIXEL_MASK; frame = (frame >> PIPE_FRAME_LOW_SHIFT) & 0xffffff; diff --git a/drivers/gpu/drm/i915/intel_uncore.h b/drivers/gpu/drm/i915/intel_uncore.h index fafc2ca9a2376..507398a562649 100644 --- a/drivers/gpu/drm/i915/intel_uncore.h +++ b/drivers/gpu/drm/i915/intel_uncore.h @@ -449,13 +449,28 @@ static inline void intel_uncore_rmw_fw(struct intel_uncore *uncore, intel_uncore_write_fw(uncore, reg, val); } +static inline u64 +intel_uncore_read64_2x32_fw(struct intel_uncore *uncore, + i915_reg_t lower_reg, i915_reg_t upper_reg) +{ + u32 upper, lower, old_upper, loop = 0; + upper = intel_uncore_read_fw(uncore, upper_reg); + do { + old_upper = upper; + lower = intel_uncore_read_fw(uncore, lower_reg); + upper = intel_uncore_read_fw(uncore, upper_reg); + } while (upper != old_upper && loop++ < 2); + + return (u64)upper << 32 | lower; +} + static inline u64 intel_uncore_read64_2x32(struct intel_uncore *uncore, i915_reg_t lower_reg, i915_reg_t upper_reg) { - u32 upper, lower, old_upper, loop = 0; enum forcewake_domains fw_domains; unsigned long flags; + u64 ret; fw_domains = intel_uncore_forcewake_for_reg(uncore, lower_reg, FW_REG_READ); @@ -466,17 +481,12 @@ intel_uncore_read64_2x32(struct intel_uncore *uncore, spin_lock_irqsave(&uncore->lock, flags); intel_uncore_forcewake_get__locked(uncore, fw_domains); - upper = intel_uncore_read_fw(uncore, upper_reg); - do { - old_upper = upper; - lower = intel_uncore_read_fw(uncore, lower_reg); - upper = intel_uncore_read_fw(uncore, upper_reg); - } while (upper != old_upper && loop++ < 2); + ret = intel_uncore_read64_2x32_fw(uncore, lower_reg, upper_reg); intel_uncore_forcewake_put__locked(uncore, fw_domains); spin_unlock_irqrestore(&uncore->lock, flags); - return (u64)upper << 32 | lower; + return ret; } static inline int intel_uncore_write_and_verify(struct intel_uncore *uncore, diff --git a/drivers/gpu/drm/xe/compat-i915-headers/intel_uncore.h b/drivers/gpu/drm/xe/compat-i915-headers/intel_uncore.h index a8cfd65119e09..6959a761fa06a 100644 --- a/drivers/gpu/drm/xe/compat-i915-headers/intel_uncore.h +++ b/drivers/gpu/drm/xe/compat-i915-headers/intel_uncore.h @@ -74,6 +74,13 @@ intel_uncore_read64_2x32(struct intel_uncore *uncore, return (u64)upper << 32 | lower; } +static inline u64 +intel_uncore_read64_2x32_fw(struct intel_uncore *uncore, + i915_reg_t i915_lower_reg, i915_reg_t i915_upper_reg) +{ + return intel_uncore_read64_2x32(uncore, i915_lower_reg, i915_upper_reg); +} + static inline void intel_uncore_posting_read(struct intel_uncore *uncore, i915_reg_t i915_reg) { -- 2.51.0