linux-kernel - Re: [PATCH 4/4] drm/amdgpu: resize VRAM BAR for CPU access

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Message-ID: <CAHp75VcSD+edusfZF8KWvCqoywPwJXdO_=9-RZdDpMF5dKtocQ@mail.gmail.com>
Date:   Mon, 13 Mar 2017 18:51:08 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Christian König <deathsimple@...afone.de>
Cc:     helgaas@...nel.org,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        dri-devel@...ts.freedesktop.org,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        amd-gfx@...ts.freedesktop.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] drm/amdgpu: resize VRAM BAR for CPU access

On Mon, Mar 13, 2017 at 2:41 PM, Christian König
<deathsimple@...afone.de> wrote:
> From: Christian König <christian.koenig@....com>
>
> Try to resize BAR0 to let CPU access all of VRAM.

> +void amdgpu_resize_bar0(struct amdgpu_device *adev)
> +{
> +       u32 size = max(ilog2(adev->mc.real_vram_size - 1) + 1, 20) - 20;
> +       int r;
> +
> +       r = pci_resize_resource(adev->pdev, 0, size);

> +

Redundant.

> +       if (r == -ENOTSUPP) {
> +               /* The hardware don't support the extension. */
> +               return;

> +

Ditto.

> +       } else if (r == -ENOSPC) {

Useless use of else. And thus of curly braces.

> +               DRM_INFO("Not enoigh PCI address space for a large BAR.");
> +       } else if (r) {
> +               DRM_ERROR("Problem resizing BAR0 (%d).", r);
> +       }
> +
> +       /* Reinit the doorbell mapping, it is most likely moved as well */
> +       amdgpu_doorbell_fini(adev);

> +       BUG_ON(amdgpu_doorbell_init(adev));

Comment why it's used here.
-- 
With Best Regards,
Andy Shevchenko