Re: [Qemu-devel] [Xen-devel][PATCH] configure: introduce --enable-xen-fb-backend

[Oleksandr Andrushchenko <andr2000@gmail.com>]

On 04/14/2017 03:12 AM, Stefano Stabellini wrote:
> On Tue, 11 Apr 2017, Oleksandr Andrushchenko wrote:
>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>>
>> For some use cases when Xen framebuffer/input backend
>> is not a part of Qemu it is required to disable it,
>> because of conflicting access to input/display devices.
>> Introduce additional configuration option for explicit
>> input/display control.
> In these cases when you don't want xenfb, why don't you just remove
> "vfb" from the xl config file? QEMU only starts the xenfb backend when
> requested by the toolstack.
>
> Is it because you have an alternative xenfb backend? If so, is it really
> fully xenfb compatible, or is it a different protocol? If it is a
> different protocol, I suggest you rename your frontend/backend PV device
> name to something different from "vfb".
>
Well, offending part is vkbd actually (for multi-touch
we run our own user-space backend which supports
kbd/ptr/mtouch), but vfb and vkbd is the same backend
in QEMU. So, I am ok for vfb, but just want vkbd off
So, there are 2 options:
1. At compile time remove vkbd and still allow vfb
2. Remove xenfb completely, if acceptable (this is my case)
>> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>> ---
>>   configure                 | 18 ++++++++++++++++++
>>   hw/display/Makefile.objs  |  2 +-
>>   hw/xen/xen_backend.c      |  2 ++
>>   hw/xenpv/xen_machine_pv.c |  4 ++++
>>   4 files changed, 25 insertions(+), 1 deletion(-)
>>
>> diff --git a/configure b/configure
>> index 476210b1b93f..b805cb908f03 100755
>> --- a/configure
>> +++ b/configure
>> @@ -220,6 +220,7 @@ xen=""
>>   xen_ctrl_version=""
>>   xen_pv_domain_build="no"
>>   xen_pci_passthrough=""
>> +xen_fb_backend=""
>>   linux_aio=""
>>   cap_ng=""
>>   attr=""
>> @@ -909,6 +910,10 @@ for opt do
>>     ;;
>>     --enable-xen-pv-domain-build) xen_pv_domain_build="yes"
>>     ;;
>> +  --disable-xen-fb-backend) xen_fb_backend="no"
>> +  ;;
>> +  --enable-xen-fb-backend) xen_fb_backend="yes"
>> +  ;;
>>     --disable-brlapi) brlapi="no"
>>     ;;
>>     --enable-brlapi) brlapi="yes"
>> @@ -1368,6 +1373,7 @@ disabled with --disable-FEATURE, default is enabled if available:
>>     virtfs          VirtFS
>>     xen             xen backend driver support
>>     xen-pci-passthrough
>> +  xen-fb-backend  framebuffer/input backend support
>>     brlapi          BrlAPI (Braile)
>>     curl            curl connectivity
>>     fdt             fdt device tree
>> @@ -2213,6 +2219,15 @@ if test "$xen_pv_domain_build" = "yes" &&
>>   	       "which requires Xen support."
>>   fi
>>   
>> +if test "$xen_fb_backend" != "no"; then
>> +   if test "$xen" = "yes"; then
>> +     xen_fb_backend=yes
>> +   else
>> +     error_exit "User requested feature Xen framebufer backend support" \
>> +                " but this feature requires Xen support."
>> +   fi
>> +fi
>> +
>>   ##########################################
>>   # Sparse probe
>>   if test "$sparse" != "no" ; then
>> @@ -5444,6 +5459,9 @@ if test "$xen" = "yes" ; then
>>     if test "$xen_pv_domain_build" = "yes" ; then
>>       echo "CONFIG_XEN_PV_DOMAIN_BUILD=y" >> $config_host_mak
>>     fi
>> +  if test "$xen_fb_backend" = "yes" ; then
>> +    echo "CONFIG_XEN_FB_BACKEND=y" >> $config_host_mak
>> +  fi
>>   fi
>>   if test "$linux_aio" = "yes" ; then
>>     echo "CONFIG_LINUX_AIO=y" >> $config_host_mak
>> diff --git a/hw/display/Makefile.objs b/hw/display/Makefile.objs
>> index 063889beaf4a..f5ec97ed4f48 100644
>> --- a/hw/display/Makefile.objs
>> +++ b/hw/display/Makefile.objs
>> @@ -5,7 +5,7 @@ common-obj-$(CONFIG_JAZZ_LED) += jazz_led.o
>>   common-obj-$(CONFIG_PL110) += pl110.o
>>   common-obj-$(CONFIG_SSD0303) += ssd0303.o
>>   common-obj-$(CONFIG_SSD0323) += ssd0323.o
>> -common-obj-$(CONFIG_XEN_BACKEND) += xenfb.o
>> +common-obj-$(CONFIG_XEN_FB_BACKEND) += xenfb.o
>>   
>>   common-obj-$(CONFIG_VGA_PCI) += vga-pci.o
>>   common-obj-$(CONFIG_VGA_ISA) += vga-isa.o
>> diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
>> index d1190041ae12..5146cbba6ca5 100644
>> --- a/hw/xen/xen_backend.c
>> +++ b/hw/xen/xen_backend.c
>> @@ -582,7 +582,9 @@ void xen_be_register_common(void)
>>       xen_set_dynamic_sysbus();
>>   
>>       xen_be_register("console", &xen_console_ops);
>> +#ifdef CONFIG_XEN_FB_BACKEND
>>       xen_be_register("vkbd", &xen_kbdmouse_ops);
>> +#endif
>>       xen_be_register("qdisk", &xen_blkdev_ops);
>>   #ifdef CONFIG_USB_LIBUSB
>>       xen_be_register("qusb", &xen_usb_ops);
>> diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
>> index 79aef4ecc37b..b731344c3f0a 100644
>> --- a/hw/xenpv/xen_machine_pv.c
>> +++ b/hw/xenpv/xen_machine_pv.c
>> @@ -68,7 +68,9 @@ static void xen_init_pv(MachineState *machine)
>>       }
>>   
>>       xen_be_register_common();
>> +#ifdef CONFIG_XEN_FB_BACKEND
>>       xen_be_register("vfb", &xen_framebuffer_ops);
>> +#endif
>>       xen_be_register("qnic", &xen_netdev_ops);
>>   
>>       /* configure framebuffer */
>> @@ -95,8 +97,10 @@ static void xen_init_pv(MachineState *machine)
>>       /* config cleanup hook */
>>       atexit(xen_config_cleanup);
>>   
>> +#ifdef CONFIG_XEN_FB_BACKEND
>>       /* setup framebuffer */
>>       xen_init_display(xen_domid);
>> +#endif
>>   }
>>   
>>   static void xenpv_machine_init(MachineClass *mc)
>> -- 
>> 2.7.4
>>