All of lore.kernel.org
 help / color / mirror / Atom feed
From: Bjorn Helgaas <helgaas@kernel.org>
To: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	David Airlie <airlied@linux.ie>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	Will Deacon <will.deacon@arm.com>,
	"Liuxinliang \(Matthew Liu\)" <z.liuxinliang@hisilicon.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Rongrong Zou <zourongrong@gmail.com>,
	Daniel Vetter <daniel.vetter@intel.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge
Date: Thu, 13 Jul 2017 06:29:38 -0500	[thread overview]
Message-ID: <20170713112938.GI4486@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <EE11001F9E5DDD47B7634E2F8A612F2E40B35F02@FRAEML521-MBX.china.huawei.com>

[+cc Ben, David, Daniel, Alex]

On Thu, Jul 13, 2017 at 10:29:25AM +0000, Gabriele Paoloni wrote:
> Hi Bjorn, Daniel
> 
> [...]
> 
> > 
> > Is this quirk useful on any arch other than arm64?  Per
> > drivers/pci/dwc/Kconfig, CONFIG_PCI_HISI depends on CONFIG_ARM64.
> > 
> > Would it make sense to put this quirk in arch/arm64/kernel/pci.c?
> 
> Indeed our host controller depends on ARM64 so maybe it would make
> sense to move the quirk arch/arm64/kernel/pci.c; however regardless
> why is it strictly required for a VGA device to be legacy one in order
> to make it the default boot device?
> i.e. couldn't we have:
> 
> diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
> index 0f5b2dd..a6b606c 100644
> --- a/drivers/gpu/vga/vgaarb.c
> +++ b/drivers/gpu/vga/vgaarb.c
> @@ -667,8 +667,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
>  	/* Deal with VGA default device. Use first enabled one
>  	 * by default if arch doesn't have it's own hook
>  	 */
> -	if (vga_default == NULL &&
> -	    ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
> +	if (vga_default == NULL) {
>  		vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
>  		vga_set_default_device(pdev);
>  	}

I don't know enough about the VGA arbiter to answer this.  This test was
part of the initial implementation: deb2d2ecd43d ("PCI/GPU: implement VGA
arbitration on Linux") by Ben.

Bjorn

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: helgaas@kernel.org (Bjorn Helgaas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge
Date: Thu, 13 Jul 2017 06:29:38 -0500	[thread overview]
Message-ID: <20170713112938.GI4486@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <EE11001F9E5DDD47B7634E2F8A612F2E40B35F02@FRAEML521-MBX.china.huawei.com>

[+cc Ben, David, Daniel, Alex]

On Thu, Jul 13, 2017 at 10:29:25AM +0000, Gabriele Paoloni wrote:
> Hi Bjorn, Daniel
> 
> [...]
> 
> > 
> > Is this quirk useful on any arch other than arm64?  Per
> > drivers/pci/dwc/Kconfig, CONFIG_PCI_HISI depends on CONFIG_ARM64.
> > 
> > Would it make sense to put this quirk in arch/arm64/kernel/pci.c?
> 
> Indeed our host controller depends on ARM64 so maybe it would make
> sense to move the quirk arch/arm64/kernel/pci.c; however regardless
> why is it strictly required for a VGA device to be legacy one in order
> to make it the default boot device?
> i.e. couldn't we have:
> 
> diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c
> index 0f5b2dd..a6b606c 100644
> --- a/drivers/gpu/vga/vgaarb.c
> +++ b/drivers/gpu/vga/vgaarb.c
> @@ -667,8 +667,7 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
>  	/* Deal with VGA default device. Use first enabled one
>  	 * by default if arch doesn't have it's own hook
>  	 */
> -	if (vga_default == NULL &&
> -	    ((vgadev->owns & VGA_RSRC_LEGACY_MASK) == VGA_RSRC_LEGACY_MASK)) {
> +	if (vga_default == NULL) {
>  		vgaarb_info(&pdev->dev, "setting as boot VGA device\n");
>  		vga_set_default_device(pdev);
>  	}

I don't know enough about the VGA arbiter to answer this.  This test was
part of the initial implementation: deb2d2ecd43d ("PCI/GPU: implement VGA
arbitration on Linux") by Ben.

Bjorn

  reply	other threads:[~2017-07-13 11:29 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-12  5:08 [PATCH v4] PCI: Support hibmc VGA cards behind a misbehaving HiSilicon bridge Daniel Axtens
2017-07-12 20:04 ` Bjorn Helgaas
2017-07-12 20:04   ` Bjorn Helgaas
2017-07-13 10:29   ` Gabriele Paoloni
2017-07-13 10:29     ` Gabriele Paoloni
2017-07-13 11:29     ` Bjorn Helgaas [this message]
2017-07-13 11:29       ` Bjorn Helgaas
2017-07-13 20:45       ` Benjamin Herrenschmidt
2017-07-13 20:45         ` Benjamin Herrenschmidt
2017-07-14 12:14         ` Gabriele Paoloni
2017-07-14 12:14           ` Gabriele Paoloni
2017-07-13 21:11       ` Alex Williamson
2017-07-13 21:11         ` Alex Williamson
2017-07-13 21:21         ` Benjamin Herrenschmidt
2017-07-13 21:21           ` Benjamin Herrenschmidt
2017-07-14 12:26           ` Gabriele Paoloni
2017-07-14 12:26             ` Gabriele Paoloni
2017-07-14 13:50             ` Benjamin Herrenschmidt
2017-07-14 13:50               ` Benjamin Herrenschmidt
2017-07-14 17:03               ` Gabriele Paoloni
2017-07-14 17:03                 ` Gabriele Paoloni
2017-07-14 23:54                 ` Benjamin Herrenschmidt
2017-07-14 23:54                   ` Benjamin Herrenschmidt
2017-07-14 14:43             ` Alex Williamson
2017-07-14 14:43               ` Alex Williamson
2017-07-14  1:35   ` Will Deacon
2017-07-14  1:35     ` Will Deacon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170713112938.GI4486@bhelgaas-glaptop.roam.corp.google.com \
    --to=helgaas@kernel.org \
    --cc=airlied@linux.ie \
    --cc=alex.williamson@redhat.com \
    --cc=benh@kernel.crashing.org \
    --cc=catalin.marinas@arm.com \
    --cc=daniel.vetter@intel.com \
    --cc=dja@axtens.net \
    --cc=gabriele.paoloni@huawei.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=will.deacon@arm.com \
    --cc=z.liuxinliang@hisilicon.com \
    --cc=zourongrong@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.