From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f193.google.com ([209.85.215.193]:38931 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726537AbeILLsf (ORCPT ); Wed, 12 Sep 2018 07:48:35 -0400 Received: by mail-pg1-f193.google.com with SMTP id i190-v6so522270pgc.6 for ; Tue, 11 Sep 2018 23:45:31 -0700 (PDT) From: Daniel Drake To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux@endlessm.com, nouveau@lists.freedesktop.org, linux-pm@vger.kernel.org, peter@lekensteyn.nl, kherbst@redhat.com, andy.shevchenko@linux.intel.com, rafael.j.wysocki@intel.com, keith.busch@intel.com, mika.westerberg@linux.intel.com, jonathan.derrick@intel.com, kugel@rockbox.org, davem@davemloft.net, hkallweit1@gmail.com, netdev@vger.kernel.org, nic_swsd@realtek.com, rchang@marvell.com Subject: [PATCH v2] PCI: Reprogram bridge prefetch registers on resume Date: Wed, 12 Sep 2018 14:45:23 +0800 Message-Id: <20180912064523.9599-1-drake@endlessm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On 38+ Intel-based Asus products, the nvidia GPU becomes unusable after S3 suspend/resume. The affected products include multiple generations of nvidia GPUs and Intel SoCs. After resume, nouveau logs many errors such as: fifo: fault 00 [READ] at 0000005555555000 engine 00 [GR] client 04 [HUB/FE] reason 4a [] on channel -1 [007fa91000 unknown] DRM: failed to idle channel 0 [DRM] Similarly, the nvidia proprietary driver also fails after resume (black screen, 100% CPU usage in Xorg process). We shipped a sample to Nvidia for diagnosis, and their response indicated that it's a problem with the parent PCI bridge (on the Intel SoC), not the GPU. Runtime suspend/resume works fine, only S3 suspend is affected. We found a workaround: on resume, rewrite the Intel PCI bridge 'Prefetchable Base Upper 32 Bits' register (PCI_PREF_BASE_UPPER32). In the cases that I checked, this register has value 0 and we just have to rewrite that value. Linux already saves and restores PCI config space during suspend/resume, but this register was being skipped because upon resume, it already has value 0 (the correct, pre-suspend value). Intel appear to have previously acknowledged this behaviour and the requirement to rewrite this register. https://bugzilla.kernel.org/show_bug.cgi?id=116851#c23 Based on that, rewrite the prefetch register values even when that appears unnecessary. We have confirmed this solution on all the affected models we have in-hands (X542UQ, UX533FD, X530UN, V272UN). Additionally, this solves an issue where r8169 MSI-X interrupts were broken after S3 suspend/resume on Asus X441UAR. This issue was recently worked around in commit 7bb05b85bc2d ("r8169: don't use MSI-X on RTL8106e"). It also fixes the same issue on RTL6186evl/8111evl on an Aimfor-tech laptop that we had not yet patched. I suspect it will also fix the issue that was worked around in commit 7c53a722459c ("r8169: don't use MSI-X on RTL8168g"). Thomas Martitz reports that this change also solves an issue where the AMD Radeon Polaris 10 GPU on the HP Zbook 14u G5 is unresponsive after S3 suspend/resume. Link: https://bugzilla.kernel.org/show_bug.cgi?id=201069 Signed-off-by: Daniel Drake --- Notes: Replaces patch: PCI: add prefetch quirk to work around Asus/Nvidia suspend issues Some of the more verbose info was moved to bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201069 This patch is aimed at v4.19 (and maybe v4.18-stable); we may follow up with more intrusive improvements for v4.20+. v2: reimplement the register restore within the existing pci_restore_config_space() code. drivers/pci/pci.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 29ff9619b5fa..e1704100e72d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1289,13 +1289,15 @@ int pci_save_state(struct pci_dev *dev) EXPORT_SYMBOL(pci_save_state); static void pci_restore_config_dword(struct pci_dev *pdev, int offset, - u32 saved_val, int retry) + u32 saved_val, int retry, bool force) { u32 val; - pci_read_config_dword(pdev, offset, &val); - if (val == saved_val) - return; + if (!force) { + pci_read_config_dword(pdev, offset, &val); + if (val == saved_val) + return; + } for (;;) { pci_dbg(pdev, "restoring config space at offset %#x (was %#x, writing %#x)\n", @@ -1313,25 +1315,34 @@ static void pci_restore_config_dword(struct pci_dev *pdev, int offset, } static void pci_restore_config_space_range(struct pci_dev *pdev, - int start, int end, int retry) + int start, int end, int retry, + bool force) { int index; for (index = end; index >= start; index--) pci_restore_config_dword(pdev, 4 * index, pdev->saved_config_space[index], - retry); + retry, force); } static void pci_restore_config_space(struct pci_dev *pdev) { if (pdev->hdr_type == PCI_HEADER_TYPE_NORMAL) { - pci_restore_config_space_range(pdev, 10, 15, 0); + pci_restore_config_space_range(pdev, 10, 15, 0, false); /* Restore BARs before the command register. */ - pci_restore_config_space_range(pdev, 4, 9, 10); - pci_restore_config_space_range(pdev, 0, 3, 0); + pci_restore_config_space_range(pdev, 4, 9, 10, false); + pci_restore_config_space_range(pdev, 0, 3, 0, false); + } else if (pdev->hdr_type == PCI_HEADER_TYPE_BRIDGE) { + pci_restore_config_space_range(pdev, 12, 15, 0, false); + /* Force rewriting of prefetch registers to avoid + * S3 resume issues on Intel PCI bridges that occur when + * these registers are not explicitly written. + */ + pci_restore_config_space_range(pdev, 9, 11, 0, true); + pci_restore_config_space_range(pdev, 0, 8, 0, false); } else { - pci_restore_config_space_range(pdev, 0, 15, 0); + pci_restore_config_space_range(pdev, 0, 15, 0, false); } } -- 2.17.1