diff options
| author | Wei Hu <weh@microsoft.com> | 2019-09-18 09:03:20 +0300 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2019-11-22 04:10:44 +0300 |
| commit | d21987d709e807ba7bbf47044deb56a3c02e8be4 (patch) | |
| tree | 39cab8ff61f1b8ab8b1d2ae317620894d115886f /drivers/video/fbdev/Kconfig | |
| parent | 67e7cdb4829d3246c98f2ec9b771303ebe162eab (diff) | |
| download | linux-d21987d709e807ba7bbf47044deb56a3c02e8be4.tar.xz | |
video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver
Without deferred IO support, hyperv_fb driver informs the host to refresh
the entire guest frame buffer at fixed rate, e.g. at 20Hz, no matter there
is screen update or not. This patch supports deferred IO for screens in
graphics mode and also enables the frame buffer on-demand refresh. The
highest refresh rate is still set at 20Hz.
Currently Hyper-V only takes a physical address from guest as the starting
address of frame buffer. This implies the guest must allocate contiguous
physical memory for frame buffer. In addition, Hyper-V Gen 2 VMs only
accept address from MMIO region as frame buffer address. Due to these
limitations on Hyper-V host, we keep a shadow copy of frame buffer
in the guest. This means one more copy of the dirty rectangle inside
guest when doing the on-demand refresh. This can be optimized in the
future with help from host. For now the host performance gain from deferred
IO outweighs the shadow copy impact in the guest.
Signed-off-by: Wei Hu <weh@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/video/fbdev/Kconfig')
| -rw-r--r-- | drivers/video/fbdev/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index 1e70e838530e..aa9541bf964b 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -2214,6 +2214,7 @@ config FB_HYPERV select FB_CFB_FILLRECT select FB_CFB_COPYAREA select FB_CFB_IMAGEBLIT + select FB_DEFERRED_IO help This framebuffer driver supports Microsoft Hyper-V Synthetic Video. |