From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karol Herbst Subject: [PATCH v4] pci: prevent putting nvidia GPUs into lower device states on certain intel bridges Date: Thu, 17 Oct 2019 14:19:01 +0200 Message-ID: <20191017121901.13699-1-kherbst@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: Karol Herbst , Bjorn Helgaas , Lyude Paul , "Rafael J . Wysocki" , Mika Westerberg , linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org Fixes state transitions of Nvidia Pascal GPUs from D3cold into higher device states. v2: convert to pci_dev quirk put a proper technical explanation of the issue as a in-code comment v3: disable it only for certain combinations of intel and nvidia hardware v4: simplify quirk by setting flag on the GPU itself Signed-off-by: Karol Herbst Cc: Bjorn Helgaas Cc: Lyude Paul Cc: Rafael J. Wysocki Cc: Mika Westerberg Cc: linux-pci@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: nouveau@lists.freedesktop.org --- drivers/pci/pci.c | 7 ++++++ drivers/pci/quirks.c | 53 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 1 + 3 files changed, 61 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b97d9e10c9cc..02e71e0bcdd7 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -850,6 +850,13 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) || (state == PCI_D2 && !dev->d2_support)) return -EIO; + /* + * check if we have a bad combination of bridge controller and nvidia + * GPU, see quirk_broken_nv_runpm for more info + */ + if (state != PCI_D0 && dev->broken_nv_runpm) + return 0; + pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); /* diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 44c4ae1abd00..0006c9e37b6f 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -5268,3 +5268,56 @@ static void quirk_reset_lenovo_thinkpad_p50_nvgpu(struct pci_dev *pdev) DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, 0x13b1, PCI_CLASS_DISPLAY_VGA, 8, quirk_reset_lenovo_thinkpad_p50_nvgpu); + +/* + * Some Intel PCIe bridges cause devices to disappear from the PCIe bus after + * those were put into D3cold state if they were put into a non D0 PCI PM + * device state before doing so. + * + * This leads to various issue different issues which all manifest differently, + * but have the same root cause: + * - AIML code execution hits an infinite loop (as the coe waits on device + * memory to change). + * - kernel crashes, as all pci reads return -1, which most code isn't able + * to handle well enough. + * - sudden shutdowns, as the kernel identified an unrecoverable error after + * userspace tries to access the GPU. + * + * In all cases dmesg will contain at least one line like this: + * 'nouveau 0000:01:00.0: Refused to change power state, currently in D3' + * followed by a lot of nouveau timeouts. + * + * ACPI code writes bit 0x80 to the not documented PCI register 0x248 of the + * PCIe bridge controller in order to power down the GPU. + * Nonetheless, there are other code paths inside the ACPI firmware which use + * other registers, which seem to work fine: + * - 0xbc bit 0x20 (publicly available documentation claims 'reserved') + * - 0xb0 bit 0x10 (link disable) + * Changing the conditions inside the firmware by poking into the relevant + * addresses does resolve the issue, but it seemed to be ACPI private memory + * and not any device accessible memory at all, so there is no portable way of + * changing the conditions. + * + * The only systems where this behavior can be seen are hybrid graphics laptops + * with a secondary Nvidia Pascal GPU. It cannot be ruled out that this issue + * only occurs in combination with listed Intel PCIe bridge controllers and + * the mentioned GPUs or if it's only a hw bug in the bridge controller. + * + * But because this issue was NOT seen on laptops with an Nvidia Pascal GPU + * and an Intel Coffee Lake SoC, there is a higher chance of there being a bug + * in the bridge controller rather than in the GPU. + * + * This issue was not able to be reproduced on non laptop systems. + */ + +static void quirk_broken_nv_runpm(struct pci_dev *dev) +{ + struct pci_dev *bridge = pci_upstream_bridge(dev); + + if (bridge->vendor == PCI_VENDOR_ID_INTEL && + bridge->device == 0x1901) + dev->broken_nv_runpm = 1; +} +DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, + PCI_BASE_CLASS_DISPLAY, 16, + quirk_broken_nv_runpm); diff --git a/include/linux/pci.h b/include/linux/pci.h index ac8a6c4e1792..903a0b3a39ec 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -416,6 +416,7 @@ struct pci_dev { unsigned int __aer_firmware_first_valid:1; unsigned int __aer_firmware_first:1; unsigned int broken_intx_masking:1; /* INTx masking can't be used */ + unsigned int broken_nv_runpm:1; /* some combinations of intel bridge controller and nvidia GPUs break rtd3 */ unsigned int io_window_1k:1; /* Intel bridge 1K I/O windows */ unsigned int irq_managed:1; unsigned int has_secondary_link:1; -- 2.21.0