Date:   Wed, 11 Oct 2017 13:53:06 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     "Thang Q. Nguyen" <tqnguyen@....com>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Adam Wallis <awallis@...eaurora.org>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: Re: [PATCH 4.13 077/160] usb: host: xhci-plat: allow sysdev to
 inherit from ACPI

On Wed, Oct 11, 2017 at 11:19:41AM +0700, Thang Q. Nguyen wrote:
> Hi,
> 
> On Wed, Oct 11, 2017 at 2:50 AM, Greg Kroah-Hartman <gregkh@...uxfoundation.org
> > wrote:
> 
>     4.13-stable review patch.  If anyone has any objections, please let me
>     know.
> 
>     ------------------
> 
>     From: Adam Wallis <awallis@...eaurora.org>
> 
>     commit c6b8e79306f515b5483eb11076e0fbfc140434a8 upstream.
> 
>     Commit 4c39d4b949d3 ("usb: xhci: use bus->sysdev for DMA configuration")
>     updated the method determining DMA for XHCI from sysdev. However, this
>     patch broke the ability to enumerate the FWNODE from parent ACPI devices
>     from the child plat XHCI device.
> 
>     Currently, xhci_plat is not set up properly when the parent device is an
>     ACPI node. The conditions that xhci_plat_probe should satisfy are
> 
>     1. xhci_plat comes from firmware
>     2. xhci_plat is child of a device from firmware (dwc3-plat)
>     3. xhci_plat is grandchild of a pci device (dwc3-pci)
> 
>     Case 2 is covered when the child is an OF node (by checking
>     sysdev->parent->of_node), however, an ACPI parent will return NULL in
>     the of_node check and will thus not result in sysdev being set to
>     sysdev->parent
> 
>     [   17.591549] xhci-hcd: probe of xhci-hcd.6.auto failed with error -5
> 
>     This change adds a check for ACPI to completely allow for condition 2.
>     This is done by first checking if the parent node is of type ACPI (e.g.,
>     dwc3-plat) and set sysdev to sysdev->parent if either of the two
>     following conditions are met:
> 
>     1: If fwnode is empty (in the case that platform_device_add_properties
>     was not called on the allocated platform device)
>     2: fwnode exists but is not of type ACPI (this would happen if
>     platform_device_add_properties was called on the allocated device.
>     Instead of type FWNODE_ACPI, you would end up with FWNODE_PDATA)
> 
>     Fixes: 4c39d4b949d3 ("usb: xhci: use bus->sysdev for DMA configuration")
>     Tested-by: Thang Q. Nguyen <tqnguyen@....com>
>     Signed-off-by: Adam Wallis <awallis@...eaurora.org>
>     Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
>     ---
>      drivers/usb/host/xhci-plat.c |   16 ++++++++++------
>      1 file changed, 10 insertions(+), 6 deletions(-)
> 
>     --- a/drivers/usb/host/xhci-plat.c
>     +++ b/drivers/usb/host/xhci-plat.c
>     @@ -186,14 +186,18 @@ static int xhci_plat_probe(struct platfo
>              * 2. xhci_plat is child of a device from firmware (dwc3-plat)
>              * 3. xhci_plat is grandchild of a pci device (dwc3-pci)
>              */
>     -       sysdev = &pdev->dev;
>     -       if (sysdev->parent && !sysdev->of_node && sysdev->parent->of_node)
>     -               sysdev = sysdev->parent;
>     +       for (sysdev = &pdev->dev; sysdev; sysdev = sysdev->parent) {
>     +               if (is_of_node(sysdev->fwnode) ||
>     +                       is_acpi_device_node(sysdev->fwnode))
>     +                       break;
>      #ifdef CONFIG_PCI
>     -       else if (sysdev->parent && sysdev->parent->parent &&
>     -                sysdev->parent->parent->bus == &pci_bus_type)
>     -               sysdev = sysdev->parent->parent;
>     +               else if (sysdev->bus == &pci_bus_type)
>     +                       break;
>      #endif
>     +       }
>     +
>     +       if (!sysdev)
>     +               sysdev = &pdev->dev;
> 
>             /* Try to set 64-bit DMA first */
>             if (WARN_ON(!sysdev->dma_mask))
> 
> 
> 
> This patch and Sriram's patches below should come together:
> 
> d64ff406e5("usb: dwc3: use bus->sysdev for DMA configuration")
> 
> 8c9f2de459("usb: dwc3: Do not set dma coherent mask")
> 
> a8c06e407e("usb: separate out sysdev pointer from usb_bus")
> 
> aeb78cda51("usb: chipidea: use bus->sysdev for DMA configuration")
> 
> 8123e4953f("usb: ehci: fsl: use bus->sysdev for DMA configuration")
> 
> 4c39d4b949("usb: xhci: use bus->sysdev for DMA configuration")
> 
> Otherwise, the below issue still happen:
> 
> [   17.591549] xhci-hcd: probe of xhci-hcd.6.auto failed with error -5
> 
>  
> 
> The first 2 above patches are in linux-stable.git/linux-4.11.y. And all above
> Sriram's patches are in linux-stable.git/linux-4.12.y. This means we need the
> followings:
> 
> - Apply this patch and 4 missing Sriram's patches into linux-4.11.y.
> 
> - Apply this patch into linux-4.12.y

Huh?  As Mathias said, all of the 4.11 and 4.12 patches are in 4.13,
right?  We better not have missed them, as that is _not_ how we do
kernel development and version branching.

Can you please verify this?

Also note that 4.11.y and 4.12.y are end-of-life, and we in the
community are not adding any new patches to it.  If you have a crazy
vendor that feels they want to maintain one of these kernel versions on
their own, then please go talk to them about it :)

thanks,

greg k-h

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