From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4DA5E12F38E; Tue, 9 Apr 2024 13:22:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712668964; cv=none; b=nes0E5OpN5rzS69tPuhao4s6iNe/WZLoVZgZsFBXsTcI3/Ua1n6yogTuZueA/xEp0UHlfP48HH7g9/vKwRCNRFAPY8CkVpsz4XG3WgHOXhsyVshD8PLvZ0+xiHCNJHcEbwYQP+u7rjzZKIRd9MD3FLgErYQUVHvVMSsGsTBic8Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712668964; c=relaxed/simple; bh=0ZWvbvLK1XD95XLQAIVSGXfXjBT4UbBzmYUhKoyHqgQ=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=e8C8I2PY/5MtH67YDfJjlGZuaMvlkBbYOgU5wLjHQEy+7CGvBlIl+b4mu0F+FwV5wtaT2byaDjFXXgxBfHitCDykCdLeXVDnhOetwJFolnICu1jG8b6KCW+Hgi20Yj4lYnq9eB+zj9C0TYEDyLfdwXJ2RXrcz/V64YVok++cx/Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XhYzTK0U; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XhYzTK0U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87502C433F1; Tue, 9 Apr 2024 13:22:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712668963; bh=0ZWvbvLK1XD95XLQAIVSGXfXjBT4UbBzmYUhKoyHqgQ=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=XhYzTK0UJbnxsl4W+kiyrvLUP+wHyBDYiX2fo8yLQSAL18XcE2l6PctoxiwC+nMwZ mdh9WfaNufQJfmz+4r92n4nIlsH/HZfkppTxCe+7qhdhVbj3aMOWDZ50MNbkh7VAHe jBUnlJDHLeIE796YBFGLiB150oKjZ/oaLG0rFUWQxkE4WXfL7Q/yibdZfY/9y6PmFT +l3lBDs3x1MaVEQv+valb+7Qjtn1oBR1xDiIrTGekuthlt6tk0epN2Pz58VlIAwm1w 2Vp/YeOgAxCmmQdCEnM+YaNaR5R79/YBSwi2FV+hkP9yXau4wh6EAMbNcG9m8OQrO9 Esaon+PCQ7wqA== Date: Tue, 9 Apr 2024 08:22:41 -0500 From: Bjorn Helgaas To: ppwaskie@kernel.org Cc: Dan Williams , linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] cxl/acpi.c: Add buggy BIOS hint for CXL ACPI lookup failure Message-ID: <20240409132241.GA2071709@bhelgaas> 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=us-ascii Content-Disposition: inline In-Reply-To: <20240407210526.8500-1-ppwaskie@kernel.org> On Sun, Apr 07, 2024 at 02:05:26PM -0700, ppwaskie@kernel.org wrote: > From: PJ Waskiewicz > > Currently, Type 3 CXL devices (CXL.mem) can train using host CXL > drivers on Emerald Rapids systems. However, on some production > systems from some vendors, a buggy BIOS exists that improperly > populates the ACPI => PCI mappings. Can you be more specific about what this ACPI => PCI mapping is? If you already know what the problem is, I'm sure this is obvious, but otherwise it's not. > This leads to the cxl_acpi > driver to fail probe when it cannot find the root port's _UID, in > order to look up the device's CXL attributes in the CEDT. > > Add a bit more of a descriptive message that the lookup failure > could be a bad BIOS, rather than just "failed." > > Signed-off-by: PJ Waskiewicz > --- > drivers/cxl/acpi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > index af5cb818f84d..56019466a09c 100644 > --- a/drivers/cxl/acpi.c > +++ b/drivers/cxl/acpi.c > @@ -504,7 +504,7 @@ static int cxl_get_chbs(struct device *dev, struct acpi_device *hb, > > rc = acpi_evaluate_integer(hb->handle, METHOD_NAME__UID, NULL, &uid); > if (rc != AE_OK) { > - dev_err(dev, "unable to retrieve _UID\n"); > + dev_err(dev, "unable to retrieve _UID. Potentially buggy BIOS\n"); > return -ENOENT; > } > > -- > 2.40.1 >