From patchwork Sat Dec 7 18:44:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Niklas Schnelle X-Patchwork-Id: 13898364 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 C931B2E822; Sat, 7 Dec 2024 18:44:28 +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=1733597068; cv=none; b=IUHT7F/oTmT8yNtdt8yqMKKPnR085F7pLXGxOh5g96UbQz/LKbbAP1oZA6I7FbWjZ8hWIbRCDBKt24TD3Er0yncTRQvuUNrjH+bTAqdIb4aKkNinfzyaAkOobPFR8B2B6uBINKQX4oOjk7bDus2OLA5YGhYqEkqaONQQkrUvKxU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733597068; c=relaxed/simple; bh=P0Tz+o0ppzWiPXWBhrr7FTaRZO/5732ZljC69tIiaeI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=pIMF30RqxQhI3MFUXomF/tVyikk6j77jWIjDp4YFfyhYYpe3hub+sTDTO45RRMH/FuYQdvMON17J4X2plm6YAA3QeG3PFC8CVLuOrvbNNHFSHdA2uIPDNuI6MfnWduezZAhLFdjkwjGnMb7pqGWMc4w4X28jRxvu2Mjua0meDCI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SNg2bEsO; 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="SNg2bEsO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15D79C4CECD; Sat, 7 Dec 2024 18:44:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733597068; bh=P0Tz+o0ppzWiPXWBhrr7FTaRZO/5732ZljC69tIiaeI=; h=From:Date:Subject:To:Cc:From; b=SNg2bEsOR26tW9s04pPMuXjOtkLwIiRN4+AdL/DXXm/fOCIbhFpl4c/alaKerOjFk eaIg9oIceNo9PDWmzSTPHZXMZ6K4+YBTDP98WlzaDPDpRSvjHR4yWDuVz0z4YrZv9Z g7aYNaue3BBfQ1ZSaRK3Ag3MCUPvH6JAGsGYwZFEjVsIM4KgUHmqWCuDuqKW4WjEuo /67eqeZNZxGveOoD0mD6VHuEGb6uuFt4SoBXas2asBs/zH1eA3sUAFCmjp72yX1vSK jQZE2+3mWzzxpZGMlIRU0LqK49N3rDaRot7xYhfY3QrGrYCUH2DlBXx0tSJpWD0wHF eVcEeVTdyrr9w== From: Niklas Schnelle Date: Sat, 07 Dec 2024 19:44:09 +0100 Subject: [PATCH] PCI/portdrv: Disable bwctrl service if port is fixed at 2.5 GT/s Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241207-fix_bwctrl_thunderbolt-v1-1-b711f572a705@kernel.org> X-B4-Tracking: v=1; b=H4sIAHiXVGcC/x2MWwqAIBAArxL7nZAWva4SEZlrLYTFag+I7p70O TAzD3hkQg9t8gDjSZ42F0GmCUzL6GYUZCKDylQhVVYJS/egrynwOoTlcAZZb2sQ2kjblDo3TW0 hxjtjNP9x17/vB+BxVCtoAAAA X-Change-ID: 20241207-fix_bwctrl_thunderbolt-bd1f96b3d98f To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, Rob Herring , Krzysztof Wilczy??ski , "Maciej W . Rozycki" , Jonathan Cameron , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J . Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , linux-kernel@vger.kernel.org, Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , Mika Westerberg , Lorenzo Pieralisi , Niklas Schnelle X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1958; i=niks@kernel.org; h=from:subject:message-id; bh=P0Tz+o0ppzWiPXWBhrr7FTaRZO/5732ZljC69tIiaeI=; b=owGbwMvMwCX2Wz534YHOJ2GMp9WSGNJDpjcGNbbuPzVVuuxeitx919Kcetv0awlCgUvmnPLNC 9p+T7K/o5SFQYyLQVZMkWVRl7PfuoIppnuC+jtg5rAygQxh4OIUgInoJTH84dryVpiRIY7laYuA xfWWy7+c1os9/zBzz+W6LTm64vGGDgz/a+3m6L533xbrtfjU9MdZfL/nWe5Mnmz//Le2z+6wiQu m8wMA X-Developer-Key: i=niks@kernel.org; a=openpgp; fpr=9DB000B2D2752030A5F72DDCAFE43F15E8C26090 Trying to enable bwctrl on a Thunderbolt port causes a boot hang on some systems though the exact reason is not yet understood. As per the spec Thunderbolt PCIe Downstream Ports have a fake Max Link Speed of 2.5 GT/s (USB4 v2 sec 11.2.1): "Max Link Speed field in the Link Capabilities Register set to 0001b (data rate of 2.5 GT/s only). Note: These settings do not represent actual throughput. Throughput is implementation specific and based on the USB4 Fabric performance." More generally if 2.5 GT/s is the only supported link speed there is no point in throtteling as this is already the lowest possible PCIe speed so don't advertise the capability stopping bwctrl from being probed on these ports. Link: https://lore.kernel.org/linux-pci/Z1R4VNwCOlh9Sg9n@wunner.de/ Fixes: 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCIe BW controller") Tested-by: Niklas Schnelle Signed-off-by: Niklas Schnelle Reviewed-by: Ilpo Järvinen Reviewed-by: Mika Westerberg --- Note: This issue causes a boot hang on my personal workstation see the Link for details. --- drivers/pci/pcie/portdrv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37 change-id: 20241207-fix_bwctrl_thunderbolt-bd1f96b3d98f Best regards, diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index 5e10306b63081b1ddd13e0a545418e2a8610c14c..e5f80e4a11aad4ce60b2ce998b40ec9fda8c653d 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -270,7 +270,8 @@ static int get_port_device_capability(struct pci_dev *dev) u32 linkcap; pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap); - if (linkcap & PCI_EXP_LNKCAP_LBNC) + if (linkcap & PCI_EXP_LNKCAP_LBNC && + (linkcap & PCI_EXP_LNKCAP_SLS) != PCI_EXP_LNKCAP_SLS_2_5GB) services |= PCIE_PORT_SERVICE_BWCTRL; }