From: Thomas Zimmermann <tzimmermann@suse.de>
To: Daniel Vetter <daniel.vetter@ffwll.ch>,
DRI Development <dri-devel@lists.freedesktop.org>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
Daniel Vetter <daniel.vetter@intel.com>,
Javier Martinez Canillas <javierm@redhat.com>,
Helge Deller <deller@gmx.de>,
linux-fbdev@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org
Subject: Re: [PATCH 04/11] video/aperture: use generic code to figure out the vga default device
Date: Wed, 11 Jan 2023 16:59:30 +0100 [thread overview]
Message-ID: <e0c0e249-30bc-c310-0175-92ea379ef0d6@suse.de> (raw)
In-Reply-To: <20230111154112.90575-4-daniel.vetter@ffwll.ch>
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Hi
Am 11.01.23 um 16:41 schrieb Daniel Vetter:
> Since vgaarb has been promoted to be a core piece of the pci subsystem
> we don't have to open code random guesses anymore, we actually know
> this in a platform agnostic way, and there's no need for an x86
> specific hack. See also 1d38fe6ee6a8 ("PCI/VGA: Move vgaarb to
> drivers/pci")
>
> This should not result in any functional change, and the non-x86
> multi-gpu pci systems are probably rare enough to not matter (I don't
> know of any tbh). But it's a nice cleanup, so let's do it.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Javier Martinez Canillas <javierm@redhat.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: linux-fbdev@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> ---
> drivers/video/aperture.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
> index 41e77de1ea82..3d8c925c7365 100644
> --- a/drivers/video/aperture.c
> +++ b/drivers/video/aperture.c
> @@ -324,13 +324,11 @@ EXPORT_SYMBOL(aperture_remove_conflicting_devices);
> */
> int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const char *name)
> {
> - bool primary = false;
> + bool primary;
> resource_size_t base, size;
> int bar, ret;
>
> -#ifdef CONFIG_X86
> - primary = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
> -#endif
> + primary = pdev == vga_default_device();
vga_default_device() is part of vgaarb and can return NULL. [1] That new
test is likely to be incorrect on many systems.
I suggest to implement a helper like fb_is_primary_device() on x86: it
uses the default VGA if set, or falls back to the original test. [2]
It's noteworthy that on most architectures, fb_is_primary_device()
returns 0. But at least on Sparc [3] and some Parisc [4] machines, it
does not.
I've long wanted to rework this helper anyway. So this is a good
opportunity.
Best regards
Thomas
[1]
https://elixir.bootlin.com/linux/latest/source/include/linux/vgaarb.h#L69
[2]
https://elixir.bootlin.com/linux/latest/source/arch/x86/video/fbdev.c#L14
[3]
https://elixir.bootlin.com/linux/latest/source/arch/sparc/include/asm/fb.h#L18
[4]
https://elixir.bootlin.com/linux/latest/source/drivers/video/console/sticore.c#L1153
>
> for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
> if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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next prev parent reply other threads:[~2023-01-11 15:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230111154112.90575-1-daniel.vetter@ffwll.ch>
2023-01-11 15:41 ` [PATCH 04/11] video/aperture: use generic code to figure out the vga default device Daniel Vetter
2023-01-11 15:59 ` Thomas Zimmermann [this message]
2023-01-11 16:51 ` Daniel Vetter
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