linux-kernel - Re: linux-next: manual merge of the pci tree with Linus' tree

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Message-ID: <ijbweytd5eadwi6misldllxfagav5sfggfu3qylehjbhv7npbs@brqvjtzzo52j>
Date: Fri, 14 Nov 2025 08:24:07 -0600
From: Lucas De Marchi <lucas.demarchi@...el.com>
To: Stephen Rothwell <sfr@...b.auug.org.au>
CC: Bjorn Helgaas <bhelgaas@...gle.com>, Lorenzo Pieralisi
	<lpieralisi@...nel.org>, Krzysztof Wilczyński
	<kwilczynski@...nel.org>, Ilpo Järvinen
	<ilpo.jarvinen@...ux.intel.com>, Linux Kernel Mailing List
	<linux-kernel@...r.kernel.org>, Linux Next Mailing List
	<linux-next@...r.kernel.org>
Subject: Re: linux-next: manual merge of the pci tree with Linus' tree

On Fri, Nov 14, 2025 at 01:13:00PM +1100, Stephen Rothwell wrote:
>Hi all,
>
>Today's linux-next merge of the pci tree got a conflict in:
>
>  drivers/gpu/drm/xe/xe_vram.c
>
>between commit:
>
>  d30203739be7 ("drm/xe: Move rebar to be done earlier")
>
>from Linus' tree and commits:
>
>  73cd7ee85e78 ("PCI: Fix restoring BARs on BAR resize rollback path")
>  348df5b30822 ("drm/xe: Remove driver side BAR release before resize")
>  af63e94f01d7 ("drm/xe/vram: Use PCI rebar helpers in resize_vram_bar()")
>
>from the pci tree.
>
>I fixed it up (but I am not happy with the result - see below) and can
>carry the fix as necessary. This is now fixed as far as linux-next is
>concerned, but any non trivial conflicts should be mentioned to your
>upstream maintainer when your tree is submitted for merging.  You may
>also want to consider cooperating with the maintainer of the conflicting
>tree to minimise any particularly complex conflicts.
>
>-- 
>Cheers,
>Stephen Rothwell
>
>diff --cc drivers/gpu/drm/xe/xe_vram.c
>index 652df7a5f4f6,10f8a73e190b..000000000000
>--- a/drivers/gpu/drm/xe/xe_vram.c
>+++ b/drivers/gpu/drm/xe/xe_vram.c
>@@@ -24,39 -24,14 +24,37 @@@
>  #include "xe_vram.h"
>  #include "xe_vram_types.h"
>
>- #define BAR_SIZE_SHIFT 20
>-
> -static void
> -_resize_bar(struct xe_device *xe, int resno, resource_size_t size)
> +/*
> + * Release all the BARs that could influence/block LMEMBAR resizing, i.e.
> + * assigned IORESOURCE_MEM_64 BARs
> + */
> +static void release_bars(struct pci_dev *pdev)
> +{
> +	struct resource *res;
> +	int i;
> +
> +	pci_dev_for_each_resource(pdev, res, i) {
> +		/* Resource already un-assigned, do not reset it */
> +		if (!res->parent)
> +			continue;
> +
> +		/* No need to release unrelated BARs */
> +		if (!(res->flags & IORESOURCE_MEM_64))
> +			continue;
> +
> +		pci_release_resource(pdev, i);
> +	}
> +}
> +
> +static void resize_bar(struct xe_device *xe, int resno, resource_size_t size)
>  {
>  	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
>  	int bar_size = pci_rebar_bytes_to_size(size);
>  	int ret;
>
> +	release_bars(pdev);
> +

https://lore.kernel.org/all/3ts3e2fwom7inbu2kzrvljo5mm7wz5ruaf6daib6cf5tk3v4al@njzufk22tcsy

the more correct fix here would be to drop the call and the entire
function since the functionality inside pci made this redundant.

thanks
Lucas De Marchi

>- 	ret = pci_resize_resource(pdev, resno, bar_size);
>+ 	ret = pci_resize_resource(pdev, resno, bar_size, 0);
>  	if (ret) {
>  		drm_info(&xe->drm, "Failed to resize BAR%d to %dM (%pe). Consider enabling 'Resizable BAR' support in your BIOS\n",
>  			 resno, 1 << bar_size, ERR_PTR(ret));