linux-kernel - [PATCH AUTOSEL 4.19 167/167] PCI: Reset both NVIDIA GPU and HDA in ThinkPad P50 workaround

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Date:   Tue,  3 Sep 2019 12:25:19 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Lyude Paul <lyude@...hat.com>, Bjorn Helgaas <bhelgaas@...gle.com>,
        Ben Skeggs <bskeggs@...hat.com>,
        Lukas Wunner <lukas@...ner.de>,
        Daniel Drake <drake@...lessm.com>,
        Aaron Plattner <aplattner@...dia.com>,
        Peter Wu <peter@...ensteyn.nl>,
        Ilia Mirkin <imirkin@...m.mit.edu>,
        Karol Herbst <kherbst@...hat.com>,
        Maik Freudenberg <hhfeuer@....de>,
        Sasha Levin <sashal@...nel.org>, linux-pci@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 167/167] PCI: Reset both NVIDIA GPU and HDA in ThinkPad P50 workaround

From: Lyude Paul <lyude@...hat.com>

[ Upstream commit ad54567ad5d8e938ee6cf02e4f3867f18835ae6e ]

quirk_reset_lenovo_thinkpad_50_nvgpu() resets NVIDIA GPUs to work around
an apparent BIOS defect.  It previously used pci_reset_function(), and
the available method was a bus reset, which was fine because there was
only one function on the bus.  After b516ea586d71 ("PCI: Enable NVIDIA
HDA controllers"), there are now two functions (the HDA controller and
the GPU itself) on the bus, so the reset fails.

Use pci_reset_bus() explicitly instead of pci_reset_function() since it's
OK to reset both devices.

[bhelgaas: commit log, add e0547c81bfcf]
Fixes: b516ea586d71 ("PCI: Enable NVIDIA HDA controllers")
Fixes: e0547c81bfcf ("PCI: Reset Lenovo ThinkPad P50 nvgpu at boot if necessary")
Link: https://lore.kernel.org/r/20190801220117.14952-1-lyude@redhat.com
Signed-off-by: Lyude Paul <lyude@...hat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Acked-by: Ben Skeggs <bskeggs@...hat.com>
Cc: Lukas Wunner <lukas@...ner.de>
Cc: Daniel Drake <drake@...lessm.com>
Cc: Aaron Plattner <aplattner@...dia.com>
Cc: Peter Wu <peter@...ensteyn.nl>
Cc: Ilia Mirkin <imirkin@...m.mit.edu>
Cc: Karol Herbst <kherbst@...hat.com>
Cc: Maik Freudenberg <hhfeuer@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pci/quirks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 311f8a33e62ff..06be52912dcdb 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5162,7 +5162,7 @@ static void quirk_reset_lenovo_thinkpad_p50_nvgpu(struct pci_dev *pdev)
 	 */
 	if (ioread32(map + 0x2240c) & 0x2) {
 		pci_info(pdev, FW_BUG "GPU left initialized by EFI, resetting\n");
-		ret = pci_reset_function(pdev);
+		ret = pci_reset_bus(pdev);
 		if (ret < 0)
 			pci_err(pdev, "Failed to reset GPU: %d\n", ret);
 	}
-- 
2.20.1