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Subject: Re: [PATCH v3 1/3] Kconfig : Remove HAS_IOMEM dependency for Graphics
 support
To:     Cornelia Huck <cohuck@redhat.com>
Cc:     Farhan Ali <alifm@linux.vnet.ibm.com>,
        Thomas Huth <thuth@redhat.com>, linux-kernel@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-fbdev@vger.kernel.org,
        geert@linux-m68k.org, tomi.valkeinen@ti.com,
        b.zolnierkie@samsung.com
References: <cover.1519053920.git.alifm@linux.vnet.ibm.com>
 <2beec7645bac82e7bdef4f6df0b9f4fe28696575.1519053920.git.alifm@linux.vnet.ibm.com>
 <cce8b082-c780-3559-4491-c39eb09482b0@redhat.com>
 <6cae85dc-76d5-1b92-ab13-a5e441eb84a0@linux.vnet.ibm.com>
 <faffcd8e-4ef6-64bc-ab11-9b48ca488ed6@de.ibm.com>
 <f658ea9e-0153-a0e3-544a-8ce575284245@de.ibm.com>
 <20180221113217.11bb1c69.cohuck@redhat.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Date:   Wed, 21 Feb 2018 12:09:20 +0100
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On 02/21/2018 11:32 AM, Cornelia Huck wrote:
> On Wed, 21 Feb 2018 11:22:38 +0100
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
>> On 02/21/2018 11:05 AM, Christian Borntraeger wrote:
>>>
>>>
>>> On 02/19/2018 05:38 PM, Farhan Ali wrote:  
>>>>
>>>>
>>>> On 02/19/2018 11:25 AM, Thomas Huth wrote:  
>>>>> On 19.02.2018 16:47, Farhan Ali wrote:  
>>>>>> The 'commit e25df1205f37 ("[S390] Kconfig: menus with depends on HAS_IOMEM.")'
>>>>>> added the HAS_IOMEM dependecy for "Graphics support". This disabled the
>>>>>> "Graphics support" menu for S390. But if we enable VT layer for S390,
>>>>>> we would also need to enable the dummy console. So let's remove the
>>>>>> HAS_IOMEM dependency.
>>>>>>
>>>>>> Move this dependency to sub menu items and console drivers that use
>>>>>> io memory.
>>>>>>
>>>>>> Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
>>>>>> ---
>>>>>>   drivers/video/Kconfig         | 21 +++++++++++----------
>>>>>>   drivers/video/console/Kconfig |  4 ++--
>>>>>>   2 files changed, 13 insertions(+), 12 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
>>>>>> index 3c20af9..8f10915 100644
>>>>>> --- a/drivers/video/Kconfig
>>>>>> +++ b/drivers/video/Kconfig
>>>>>> @@ -3,7 +3,6 @@
>>>>>>   #
>>>>>>     menu "Graphics support"
>>>>>> -    depends on HAS_IOMEM
>>>>>>     config HAVE_FB_ATMEL
>>>>>>       bool
>>>>>> @@ -11,20 +10,22 @@ config HAVE_FB_ATMEL
>>>>>>   config SH_LCD_MIPI_DSI
>>>>>>       bool
>>>>>>   -source "drivers/char/agp/Kconfig"
>>>>>> +if HAS_IOMEM
>>>>>> +    source "drivers/char/agp/Kconfig"
>>>>>>   -source "drivers/gpu/vga/Kconfig"
>>>>>> +    source "drivers/gpu/vga/Kconfig"
>>>>>>   -source "drivers/gpu/host1x/Kconfig"
>>>>>> -source "drivers/gpu/ipu-v3/Kconfig"
>>>>>> +    source "drivers/gpu/host1x/Kconfig"
>>>>>> +    source "drivers/gpu/ipu-v3/Kconfig"
>>>>>>   -source "drivers/gpu/drm/Kconfig"
>>>>>> +    source "drivers/gpu/drm/Kconfig"  
>>>
>>>
>>> Hmmm, looks like that this makes it impossible to select VIRTIO_GPU - need still more
>>> work.
>>>   
>> Sorry my fault. I had CONFIG_PCI disabled.
> 
> That smells like the s390 HAS_IOMEM stuff needs more work -- I guess
> that you want to enable a ccw virtio-gpu device, not a pci one, right?

It is a ccw virtio-gpu. But s390 has no IOMEM without CONFIG_PCI, so you cannot
select VIRTIO_GPU, which needs DRM, which need IOMEM.
In essence this patch is good enough to go forward and to build a sane .config
(Usually any s390 distro kernel should enable CONFIG_PCI).