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SubjectRe: PCI: Disable not requested resource types in pci_enable_resources
On Thu, May 28, 2020 at 08:47:12PM +0200, Heiner Kallweit wrote:
> Currently, if both resource types are enabled before the call, the mask
> value doesn't matter. Means as of today I wouldn't be able to e.g.
> disable PCI_COMMAND_IO. At least my interpretation is that mask defines
> which resource types are enabled after the call. Therefore change the
> behavior to disable not requested resource types.
>
> At least on my x86 devices this change doesn't have side effects.

Does this have a practical benefit? If it fixes a bug or if there's
something useful we can do because of this patch, I'll push it higher
up the priority list.

> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> drivers/pci/setup-res.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index d21fa04fa..6ef458c10 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -459,8 +459,8 @@ int pci_enable_resources(struct pci_dev *dev, int mask)
> int i;
> struct resource *r;
>
> - pci_read_config_word(dev, PCI_COMMAND, &cmd);
> - old_cmd = cmd;
> + pci_read_config_word(dev, PCI_COMMAND, &old_cmd);
> + cmd = old_cmd & ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
>
> for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> if (!(mask & (1 << i)))
> --
> 2.26.2
>

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