From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C572D3E0724 for ; Fri, 14 Aug 2026 07:05:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786691132; cv=none; b=QfyqccIylPjadMyO1iMqE/QaXmj5Gi44Z9TQosk2accatPjkFK8EnyyhDLxhEivF1czn3CIC+QcZ03A614A97X2GiWdZIaFABnAI3sATObcoXSNLTobVunIV7oJHQqKi8QvcX8Cq1d0uBQSV84q0m3tm/eQmQVu0c8YqLBjMObs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786691132; c=relaxed/simple; bh=02nlSrqU4pGt5kWyA71im4Cstzjad/spivQipb2XnI4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TIOHnesnumyEvh+8FbzUCoyEkYsu3hkA7XjPUCNOLsoEFZphRvoj0eG4zITk34QaGi836WWu4p+we8wd1WLUzao/8uGkktsmKpmFW+KJIY3EwgYvOx4NxLcmfpE5MAmu0zfAGEFgdoGkg+KwpzdqSpjM94VZVyPg/G/8SjFiG5A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DTmy65dX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DTmy65dX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C62F41F00A3A; Fri, 14 Aug 2026 07:05:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786691127; bh=uoT0vcEMsySXtn4Fgf4b4dyRs3/autwjCBUGceosK0g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DTmy65dX5L7xzAMxTt22pitDKeCovm1dhaRmYe+tIJuJzqw1Mr5mAsKqD73PSBStW 82MCngx4XvMrKG4qrlONzxwNdNa8CfZHhYxbTmECytiR3slwwiAQlAeIWaQ7ddGfWV WvowIMbMEKjZsm8EjHFtehM/hnPBsJOSqIKGc3RZ7v28xg/vnYHqztBMpWsY29n+5b VcE48M0D4jGSp+0M9kwvbRwWgK066L4mwdqYJ/KCioWPd++L3MKwMvjPB+298CnWaH 5+IefncWhtngWgZtHLkytkOscfF6Ih9GTRGfJNizdyaZI+6HiFuQtpHFE1nIE05FVk O5YD0wh1JvqOw== From: =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Bjorn Helgaas , Manivannan Sadhasivam , Lorenzo Pieralisi , "Rafael J. Wysocki" , Narendra K , linux-pci@vger.kernel.org Subject: [PATCH 1/4] PCI/sysfs: Stop reporting _DSM failures as -EPERM Date: Fri, 14 Aug 2026 07:05:19 +0000 Message-ID: <20260814070522.2327975-2-kwilczynski@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260814070522.2327975-1-kwilczynski@kernel.org> References: <20260814070522.2327975-1-kwilczynski@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, dsm_get_label() returns the literal -1 on every failure path. The sysfs read path passes that value to userspace as -EPERM. Reading the "label" or "acpi_index" attribute on a platform where the Device Name _DSM returns a malformed result then fails with: $ cat /sys/bus/pci/devices/0000:00:08.3/label cat: /sys/bus/pci/devices/0000:00:08.3/label: Operation not permitted Nothing in that path performs a permission check, and the read fails the same way for a privileged reader. The error code points at a cause that does not exist, and tools such as lspci report it on every invocation. Thus, return -ENODEV when the device has no ACPI companion, and -EIO when the _DSM evaluation fails or returns an object that cannot be parsed. Other _DSM users in the tree report such failures the same way. The set of reads that succeed, and the bytes they return, stay the same. Only the error code of reads that already fail differs. Link: https://github.com/pciutils/pciutils/issues/175 Fixes: 6058989bad05 ("PCI: Export ACPI _DSM provided firmware instance number and string name to sysfs") Signed-off-by: Krzysztof Wilczyński --- drivers/pci/pci-label.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c index 0c6446519640..255e0ecffb09 100644 --- a/drivers/pci/pci-label.c +++ b/drivers/pci/pci-label.c @@ -160,12 +160,12 @@ static int dsm_get_label(struct device *dev, char *buf, int len = 0; if (!handle) - return -1; + return -ENODEV; obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2, DSM_PCI_DEVICE_NAME, NULL); if (!obj) - return -1; + return -EIO; tmp = obj->package.elements; if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 && @@ -190,7 +190,7 @@ static int dsm_get_label(struct device *dev, char *buf, ACPI_FREE(obj); - return len > 0 ? len : -1; + return len > 0 ? len : -EIO; } static ssize_t label_show(struct device *dev, struct device_attribute *attr, -- 2.55.0