linux-kernel - Re: [PATCH] drm: Require PCI for selecting VGA

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Date:   Tue, 8 Jan 2019 16:56:37 +0100
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     dri-devel@...ts.freedesktop.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-pci@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH] drm: Require PCI for selecting VGA_ARB.

Dear Maarten,


Thank you very much for the quick response.

On 01/08/19 16:37, Maarten Lankhorst wrote:
> Op 08-01-2019 om 16:07 schreef Paul Menzel:

>> Building Linux 5.0-rc1 fails with the errors below. Please find the
>> configuration file attached.
>>
>> ```
>> $ make -j120
>> […]
>> drivers/gpu/vga/vgaarb.c: In function ‘__vga_tryget’:
>> drivers/gpu/vga/vgaarb.c:286:14: error: ‘PCI_VGA_STATE_CHANGE_DECODES’ undeclared (first use in this function); did you mean ‘PCI_SUBTRACTIVE_DECODE’?
>>      flags |= PCI_VGA_STATE_CHANGE_DECODES;
>>               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>               PCI_SUBTRACTIVE_DECODE
>> drivers/gpu/vga/vgaarb.c:286:14: note: each undeclared identifier is reported only once for each function it appears in
>>   CC [M]  net/netfilter/xt_realm.o
>>   CC      drivers/hid/hid-cherry.o
>> drivers/gpu/vga/vga_switcheroo.c: In function ‘vga_switcheroo_runtime_suspend’:
>> drivers/gpu/vga/vga_switcheroo.c:1053:2: error: implicit declaration of function ‘pci_bus_set_current_state’; did you mean ‘__set_current_state’? [-Werror=implicit-function-declaration]
>>   pci_bus_set_current_state(pdev->bus, PCI_D3cold);
>>   ^~~~~~~~~~~~~~~~~~~~~~~~~
>>   __set_current_state
>> drivers/gpu/vga/vgaarb.c:291:13: error: ‘PCI_VGA_STATE_CHANGE_BRIDGE’ undeclared (first use in this function); did you mean ‘PCI_VGA_STATE_CHANGE_DECODES’?
>>     flags |= PCI_VGA_STATE_CHANGE_BRIDGE;
>>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>>              PCI_VGA_STATE_CHANGE_DECODES
>>   CC      fs/reiserfs/dir.o
>>   LD [M]  net/tipc/tipc.o
>> drivers/gpu/vga/vga_switcheroo.c: In function ‘vga_switcheroo_runtime_resume’:
>> drivers/gpu/vga/vga_switcheroo.c:1067:2: error: implicit declaration of function ‘pci_wakeup_bus’; did you mean ‘__wake_up_bit’? [-Werror=implicit-function-declaration]
>>   pci_wakeup_bus(pdev->bus);
>>   ^~~~~~~~~~~~~~
>>   __wake_up_bit
>> drivers/gpu/vga/vgaarb.c:293:3: error: implicit declaration of function ‘pci_set_vga_state’; did you mean ‘pci_set_power_state’? [-Werror=implicit-function-declaration]
>>    pci_set_vga_state(conflict->pdev, false, pci_bits, flags);
>>    ^~~~~~~~~~~~~~~~~
>>    pci_set_power_state
>>   CC      fs/read_write.o
>>   CC      drivers/hid/hid-chicony.o
>>   CC      drivers/hid/hid-cypress.o
>> drivers/gpu/vga/vgaarb.c: In function ‘vga_arb_device_init’:
>> drivers/gpu/vga/vgaarb.c:1495:25: error: ‘pci_bus_type’ undeclared (first use in this function); did you mean ‘pci_pcie_type’?
>>   bus_register_notifier(&pci_bus_type, &pci_notifier);
>>                          ^~~~~~~~~~~~
>>                          pci_pcie_type
>> cc1: some warnings being treated as errors
>> make[3]: *** [scripts/Makefile.build:277: drivers/gpu/vga/vgaarb.o] Error 1
>> make[3]: *** Waiting for unfinished jobs....
>> […]
>> ```

> WARNING: unmet direct dependencies detected for VGA_ARB
>   Depends on [n]: HAS_IOMEM [=y] && PCI [=n] && !S390
>   Selected by [y]:
>   - VGA_SWITCHEROO [=y] && HAS_IOMEM [=y] && X86 [=y] && ACPI [=y]
> 
> So I guess you need to enable PCI, probably not a common config you're using. :)
> 
> Especially since you selected EXPERT.

We have the attached defconfig, which is then integrated using
`make olddefconfig`.

> Oh well, apply this with git am --scissors?
> -----8<----
> When configuring the kernel without PCI we can still enable VGA switcheroo,
> which is not possible because VGA_ARB cannot be selected.
> 
> Remove this by depending on PCI for !S390.
> 
> Reported-by: Paul Menzel <pmenzel@...gen.mpg.de>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> ---
> diff --git a/drivers/gpu/vga/Kconfig b/drivers/gpu/vga/Kconfig
> index b677e5d524e6..ef5671475870 100644
> --- a/drivers/gpu/vga/Kconfig
> +++ b/drivers/gpu/vga/Kconfig
> @@ -21,6 +21,7 @@ config VGA_SWITCHEROO
>  	bool "Laptop Hybrid Graphics - GPU switching support"
>  	depends on X86
>  	depends on ACPI
> +	depends on (PCI && !S390) # For VGA_ARB
>  	select VGA_ARB
>  	help
>  	  Many laptops released in 2008/9/10 have two GPUs with a multiplexer

Is this an effect of commit eb01d42a (PCI: consolidate PCI config entry in
drivers/pci) as the `default y` is missing now?


Kind regards,

Paul

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