From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B6E7D41CB3A for ; Mon, 13 Jul 2026 13:07:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=209.85.215.175 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783948046; cv=pass; b=JjCXAtjOnNg0HvpjLn+twagfXkpmKGSE0shqCDcvsrQfl+X2Keh2nvWiei57FG8y5KR8fp0qxZ/VMvfOVWLVcSKO+YcIxKeM63o+ReM8lZ0hnv3B17vjaziI+q1SEGeh+F2HiEsv+wrfXKQ9ufJNLjbdgkvzYci5IEqNG9HQ3fI= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783948046; c=relaxed/simple; bh=Uj6Bq4yqRSdDVWgocVXkGYuTG/yfXUB29fBsrpNa/UA=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=ajYsmxzVVDZ5FyOXutg1E4PZXXBeN14PQICy3o/w9b4JsfbII4DIq1k0RmyC+dhDJ9IF6VkN5x+Z0GYT4+RyzIbqpOglhxTg9oLsieAydVmn8CQyAyt5KHVlly7uLVHB3YIHddABN9XqCHJWwHqnG7+O4xCGvWowyoZQZ/tgDW0= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QIdmVCTd; arc=pass smtp.client-ip=209.85.215.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QIdmVCTd" Received: by mail-pg1-f175.google.com with SMTP id 41be03b00d2f7-c96c92c0980so1625045a12.3 for ; Mon, 13 Jul 2026 06:07:25 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1783948045; cv=none; d=google.com; s=arc-20260327; b=px0qgmDKKSP9sSFBJwJytjx+inGSTccZv6EATdELO2mn6ju3zEHzZgFb5K3DBRFTI7 hQsJoQ69BwkHswJul+QwiHc1grj+IMvOH/J5R475vDlxfPpvD6+wkIw8+54zZEnPGMWr 0kRQqZzeQreJ3cZUt6Uh0nI1QPxdmCkIDmvaVhNFerW16okHpeDzR9+ZV+oriwU+fhgf N0SO3HAsfiq00fdpSUcKad6G2csJ3YEkOTegtkDAlxsuSa2ZxGEHE6AXmXHLvyEvlqaA 2znoHd8zcFPSjsQHmpF1Y6bMuGDYBw7v7yyco/Pbryq6+x6bqGyIK+HPYJBw5DBgXb/9 R1/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20260327; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=2Fqx/czp6jQUNV38u5qUVP1ElD+PeQ9iFnGsUGSfqqU=; fh=8+kfJhXuJBeWH41Wa9BPB9BTxoGJb2TxPxY/7BL14aA=; b=lznDrrMW6KHpA5m/aiCyLp7n0faX/08pC2z8giBgaIc1Mx+6KbBuqBPhILPSKQKpEU JPC4oS29iDQZ7Zcbz0sj68BpqzyRrtr14OsqWSKNyfvK2443wb2gNBRa6TnpYBKLqCgp qQ2VY2ySCMNp2XXzHxNNnYMgtYmXZKzXpDLzPT7xEdrxvbOi9D+Yjbxey3LWQmzYrj2i 2vHsNvfWVjIcx5DA2TwuWpjdw5/BgWLS30qhf0AHz/5LsnuZb1dRof0o8CAzUnH5C6fN uY4cQM66w3KZMQGnVLT9aTjoLWhIXrH8D/VgnxkShuGtSsy+/phBoB4BiC4uf8ygg5oI lMyw==; darn=vger.kernel.org ARC-Authentication-Results: i=1; mx.google.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783948045; x=1784552845; darn=vger.kernel.org; h=content-type:cc:to:subject:message-id:date:from:in-reply-to :references:mime-version:from:to:cc:subject:date:message-id:reply-to :content-type; bh=2Fqx/czp6jQUNV38u5qUVP1ElD+PeQ9iFnGsUGSfqqU=; b=QIdmVCTdFsoodYsnU9eh1tjHFiiBw+QYcy87q43h/wEEmLKJkhNLT+3Su4QRhFug9o spCE6IMbCdM0bXhLP1MSU4GAtCo9UvA7J2XvfEm89aJ9mCWste2qrFTQKelqiWu4O/Yi WiKtz2UpYU0C//WhIqQJNr8lmK6BQ/urgI0dy6UY04Nu/OhXr1j0QCr/vwbq+18vAn3t kMU3LLnoBx5cLc+iaBdIGA/TbxB/YlMxYOQubcdNQqCl2xYPzuIWl9gTZAOhFJmYAHww ZZUSaA0V+gUIY7xvNjntBYdKojQsAiGs992STm+/Dp76vsL2x+4BO5BRFUIeE9B7eQMf zrZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783948045; x=1784552845; h=content-type:cc:to:subject:message-id:date:from:in-reply-to :references:mime-version:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to:content-type; bh=2Fqx/czp6jQUNV38u5qUVP1ElD+PeQ9iFnGsUGSfqqU=; b=H+hEZnpypBlhYsEPSS5NrziHOBE6pRTDsFFAd4MQbokm2K0wpzohEQ0HwXPjd2SYj2 rdngXCPSHIY80woLJ4aNQtlWGjAoCPdQzeAJ8DrjfqGc3nXXjuGhv/JKJCXyH47X+bAS GDKAhbu2SlWi5YSXlMzic2uPJnta5AI8wxXeDKWM1DOGZSHofIUo1v7AaUF3Kk+J5X+X Vrzv2cKL9bUqA9PiJq1HgPiQcr1zTdfASWwU4ktXHktIxDE4Eu6WIMp4x503W49JPFx/ R7rujl6Mzy3234pdH9krBbChs3uxM/HCCBkbyml3LUdgS2BfEscD1JLZsVWW6AjtbheV SHzg== X-Forwarded-Encrypted: i=1; AHgh+RpAvzNGZ19jdGrpmAis9wSHsYfBSPiPAwdLx/ChvnEPrdvto8/VHdfuUUijeP0G+rVYjARMWnoGPG/mTU4=@vger.kernel.org X-Gm-Message-State: AOJu0YxMxVB7tHZkq1fwEUpTZY3mV3Z9UcHlEq35GFCQrntjzLox0YSx 2o5SK1KVGmS7/OCCguxwBEAAP/7jV3cv4aMg/BeAmx7qg0ptTr5luMDOQw/1jt900wegH07HOFM eO2PjrOzfbYLTh1JXBRwQEyhZDGhdoA0= X-Gm-Gg: AfdE7cm4+HKgicqnjSqCMjmT5j0Guq8ChdTWdyI01p6B3x3cBwQAZFvpJQcoCRQ/EPE UIVOeu+30OJ/2WBjW6L4DRcK/ISUww0zBWEyEpZjt844pzQmdrpP0bOlX87mpAm/prnD0PRuyBL iGlCU5ohAqsiSW5jVidbwVEzfsxrDIltiL78JlFHCpvQ9E9eriwK8zin0TefokI97At1lB83C6u PGVmS5ggi0vE750y+qRkskfq3DvsFN2Gb+ahUjMa5klFByjhYx7jxr3tFdoPwBVKze+dMeGtrj5 m+TEajJSQHCgLhGTZysH4kI37VuhZf7mKPre1MnxCUoajLXln1R3bbxD94g+bA== X-Received: by 2002:a05:6a21:32a2:b0:3bf:6237:4d4a with SMTP id adf61e73a8af0-3c1108c0ad0mr10164721637.24.1783948044948; Mon, 13 Jul 2026 06:07:24 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260713073059.47914-1-phucduc.bui@gmail.com> <24ce60c7-5539-4fba-8bf3-3a10875c3b75@sirena.org.uk> In-Reply-To: <24ce60c7-5539-4fba-8bf3-3a10875c3b75@sirena.org.uk> From: Bui Duc Phuc Date: Mon, 13 Jul 2026 20:07:13 +0700 X-Gm-Features: AVVi8CfkJmByub5tQXV2QE6hKgT1oI4wRsJZFzUYZ3a0E1lOIwNn_pP9BYAZsT8 Message-ID: Subject: Re: [PATCH] regcache: disable cache_only before rewriting paging registers To: Mark Brown Cc: Greg Kroah-Hartman , rafael@kernel.org, Danilo Krummrich , linux-kernel@vger.kernel.org, driver-core@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Hi Mark, Thanks for the feedback. > > No, any access to the hardware is buggy - the whole point of cache only > mode is that we can't access the hardware. The paging register is part > of the context that needs to be rewritten when resyncing the cache. To provide some context: I based this patch on your previous commit here: https://patchew.org/linux/20231026-regmap-fix-selector-sync-v1-1-633ded82770d@kernel.org/ Reading that commit, I mistakenly understood that we must enforce the hardware writes here at all costs. However, based on your explanation, I see that I misunderstood the architectural intent. Just to clarify for my understanding: does this mean regcache_sync() is strictly expected to be called only after cache_only has been set to false? If so, I will drop this patch. Best regards, Phuc