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

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Date:   Tue, 8 Jan 2019 11:07:00 -0500
From:   Sinan Kaya <Okaya@...nel.org>
To:     Paul Menzel <pmenzel@...gen.mpg.de>
Cc:     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>,
        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.

On 1/8/19, Paul Menzel <pmenzel@...gen.mpg.de> wrote:
> 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?
>

See this :

https://patchwork.kernel.org/patch/10749209/

This change is about to go in.

>
> Kind regards,
>
> Paul
>