linux-kernel - Re: [PATCH] PCI: Use pci_reset_bus() in quirk_reset_lenovo_thinkpad_50

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Message-ID: <20190815221522.GH253360@google.com>
Date:   Thu, 15 Aug 2019 17:15:22 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Lyude Paul <lyude@...hat.com>
Cc:     nouveau@...ts.freedesktop.org, linux-pci@...r.kernel.org,
        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>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: Use pci_reset_bus() in
 quirk_reset_lenovo_thinkpad_50_nvgpu()

On Thu, Aug 01, 2019 at 06:01:17PM -0400, Lyude Paul wrote:
> Since quirk_nvidia_hda() was added there's now two nvidia device
> functions on any laptops with nvidia GPUs: the HDA controller, and the
> GPU itself. Unfortunately this has the sideaffect of breaking
> quirk_reset_lenovo_thinkpad_50_nvgpu() since pci_reset_function() was
> using pci_parent_bus_reset() to reset the GPU's respective PCI bus, and
> pci_parent_bus_reset() does not work on busses which have more then a
> single device function present.
> 
> So, fix this by simply calling pci_reset_bus() instead which properly
> resets the GPU bus and all device functions under it, including both the
> GPU and the HDA controller.
> 
> Fixes: b516ea586d71 ("PCI: Enable NVIDIA HDA controllers")
> Cc: Lukas Wunner <lukas@...ner.de>
> Cc: Daniel Drake <drake@...lessm.com>
> Cc: Bjorn Helgaas <bhelgaas@...gle.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>
> Cc: linux-pci@...r.kernel.org
> Signed-off-by: Lyude Paul <lyude@...hat.com>

We merged b516ea586d71 for v5.3, so I applied this with Ben's ack to
for-linus for v5.3, thanks!

> ---
>  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 208aacf39329..44c4ae1abd00 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -5256,7 +5256,7 @@ 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);
>  	}
> -- 
> 2.21.0
>