From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A3893CAE8A; Tue, 14 Apr 2026 10:22:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776162145; cv=none; b=UFFdeJgXR12zwdB7TEQbbmTsfgXHxs6b50sMF1TvHgw0G0dz9JOdQs0NzJ30BeZvfCQB8yMvvp8QMYP5JaX5g8EFPeNEl7jpjo1jOx5L0zqVnhmo6lYd1uDEZaIadD1PyCT2gGTv/drlwSq7a/SBK6Ce6E+YiA0TUurV88rBK0g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776162145; c=relaxed/simple; bh=JoIcecRZx/cQixKD4S3F/oJmW8C02rdzT3SvIMdRREk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kqtsWYIFcYxDvBSU+p6LWjKFwLcHrziGgXaikIl9bB8KsldM5kKPnRWZFzqxh+BT00wCudcKbfQgDL0ne5qIEP9gDd+M6JysDZn4HjIIq/MSH2Ys9sC+oHDGDCgCXxRJK5g5eoA/ZbGmrBvZQP7m6ylpx+ew0I+LbyKBRw7piFg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org; spf=none smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=Sqz9M3LX; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="Sqz9M3LX" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-ID:Content-Description; bh=mrj0TgymHiMmZwZs2Vo2Bt+4CUgM0die06+x7rWw59g=; b=Sqz9M3LXIsN+s1ZYgdcBHfRdjS BQPb0aiMYyE7+TUmuI9k6GybWCOqYRsB0itaIgQTGeTMoVAUOdoJxQpEvYwRRrl6oVLDShTM+qSHh F2A1W8mDhStkHA3/nwcRkkPFUjzP1WUr8qt2Szs2vjoGJi+5ecSuy148Mq0jkNNHjztEcceX7/VkS iVp1Eje/IrkowGM61e39a8ELoRKv4Nv3q8s4b7Z8yrIjLh+uV9MVCxT9fBymiIEnCAj2/VcO+muUp vIenLrg9CivGsD8GxC4anEpwCsbGEuFx3wHXO5TXWuyTGFWIYXfWWvzNeWhyzBGDPjAnJmJVb+s8p xKErlGwA==; Received: from authenticated user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wCau0-00CzuK-0k; Tue, 14 Apr 2026 10:21:52 +0000 Date: Tue, 14 Apr 2026 03:21:46 -0700 From: Breno Leitao To: "lihuisong (C)" Cc: "Rafael J. Wysocki" , Len Brown , lpieralisi@kernel.org, catalin.marinas@arm.com, will@kernel.org, "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, pjaroszynski@nvidia.com, guohanjun@huawei.com, sudeep.holla@kernel.org, linux-arm-kernel@lists.infradead.org, rmikey@meta.com, kernel-team@meta.com Subject: Re: [PATCH RFC] ACPI: processor: idle: Do not propagate acpi_processor_ffh_lpi_probe() -ENODEV Message-ID: References: <20260413-ffh-v1-1-301704f69e2f@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Debian-User: leitao Hello Huisong, On Tue, Apr 14, 2026 at 05:43:51PM +0800, lihuisong (C) wrote: > But it is a real issue. Thanks for your report. > I think the best way to fix your issue is that remove this verification in > psci_acpi_cpu_init_idle(). > Because it is legal for platform to report one LPI state. > This function just needs to verify the LPI states which are FFH. Thank you for the prompt feedback. Would this approach work? commit 6c9d52840a4f778cc989838ba76ee51416e85de3 Author: Breno Leitao Date: Tue Apr 14 03:16:08 2026 -0700 ACPI: processor: idle: Allow platforms with only one LPI state psci_acpi_cpu_init_idle() rejects platforms where power.count - 1 <= 0 by returning -ENODEV. However, having a single LPI state (WFI) is a valid configuration. The function's purpose is to verify FFH idle states, and when count is zero, there are simply no FFH states to validate — this is not an error. On NVIDIA Grace (aarch64) systems with PSCIv1.1, power.count is 1 for all 72 CPUs, so the probe fails with -ENODEV. After commit cac173bea57d ("ACPI: processor: idle: Rework the handling of acpi_processor_ffh_lpi_probe()"), this failure propagates up and prevents cpuidle registration entirely. Change the check from (count <= 0) to (count < 0) so that platforms with only WFI are accepted. The for loop naturally handles count == 0 by not iterating. Fixes: cac173bea57d ("ACPI: processor: idle: Rework the handling of acpi_processor_ffh_lpi_probe()") Signed-off-by: Breno Leitao diff --git a/drivers/acpi/arm64/cpuidle.c b/drivers/acpi/arm64/cpuidle.c index 801f9c4501425..7791b751042ce 100644 --- a/drivers/acpi/arm64/cpuidle.c +++ b/drivers/acpi/arm64/cpuidle.c @@ -31,7 +31,7 @@ static int psci_acpi_cpu_init_idle(unsigned int cpu) return -EOPNOTSUPP; count = pr->power.count - 1; - if (count <= 0) + if (count < 0) return -ENODEV; for (i = 0; i < count; i++) {