Re: [PATCH v4 3/3] s390/setup : enable display support for KVM guest

[Christian Borntraeger]

Greg FYI, I plan to carry this patch via the s390/kvm tree.
As it drivers/tty/Kconfig, can you give an ack for this part?


On 02/22/2018 05:22 PM, Farhan Ali wrote:
> The S390 architecture does not support any graphics hardware,
> but with the latest support for Virtio GPU in Linux and Virtio
> GPU emulation in QEMU, it's possible to enable graphics for
> S390 using the Virtio GPU device.
> 
> To enable display we need to enable the Linux Virtual Terminal (VT)
> layer for S390. But the VT subsystem initializes quite early
> at boot so we need a dummy console driver till the Virtio GPU
> driver is initialized and we can run the framebuffer console.
> 
> The framebuffer console over a Virtio GPU device can be run
> in combination with the serial SCLP console (default on S390).
> The SCLP console can still be accessed by management applications
> (eg: via Libvirt's virsh console).
> 
> Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxxxxxxx>
> Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Reviewed-by: Thomas Huth <thuth@xxxxxxxxxx>
> ---
>  arch/s390/kernel/setup.c      | 2 ++
>  drivers/tty/Kconfig           | 2 +-
>  drivers/video/console/Kconfig | 2 +-
>  3 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
> index a6a91f0..f98a0f3 100644
> --- a/arch/s390/kernel/setup.c
> +++ b/arch/s390/kernel/setup.c
> @@ -221,6 +221,8 @@ static void __init conmode_default(void)
>  		SET_CONSOLE_SCLP;
>  #endif
>  	}
> +	if (IS_ENABLED(CONFIG_VT) && IS_ENABLED(CONFIG_DUMMY_CONSOLE))
> +		conswitchp = &dummy_con;
>  }
> 
>  #ifdef CONFIG_CRASH_DUMP
> diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
> index b811442..5ca53fa 100644
> --- a/drivers/tty/Kconfig
> +++ b/drivers/tty/Kconfig
> @@ -11,7 +11,7 @@ if TTY
> 
>  config VT
>  	bool "Virtual terminal" if EXPERT
> -	depends on !S390 && !UML
> +	depends on !UML
>  	select INPUT
>  	default y
>  	---help---
> diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
> index 9485857..b9c2c91 100644
> --- a/drivers/video/console/Kconfig
> +++ b/drivers/video/console/Kconfig
> @@ -9,7 +9,7 @@ config VGA_CONSOLE
>  	depends on !4xx && !PPC_8xx && !SPARC && !M68K && !PARISC && !FRV && \
>  		!SUPERH && !BLACKFIN && !AVR32 && !MN10300 && !CRIS && \
>  		(!ARM || ARCH_FOOTBRIDGE || ARCH_INTEGRATOR || ARCH_NETWINDER) && \
> -		!ARM64 && !ARC && !MICROBLAZE && !OPENRISC && HAS_IOMEM
> +		!ARM64 && !ARC && !MICROBLAZE && !OPENRISC && HAS_IOMEM && !S390
>  	default y
>  	help
>  	  Saying Y here will allow you to use Linux in text mode through a
>