> -----Original Message----- > From: Gerd Hoffmann [mailto:kraxel@xxxxxxxxxx] > Sent: Thursday, June 27, 2019 2:23 PM > To: Zhang, Tina <tina.zhang@xxxxxxxxx> > Cc: intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; zhenyuw@xxxxxxxxxxxxxxx; Lv, Zhiyuan > <zhiyuan.lv@xxxxxxxxx>; Wang, Zhi A <zhi.a.wang@xxxxxxxxx>; Tian, Kevin > <kevin.tian@xxxxxxxxx>; Yuan, Hang <hang.yuan@xxxxxxxxx>; > alex.williamson@xxxxxxxxxx > Subject: Re: [RFC PATCH v3 0/4] Deliver vGPU display vblank event to > userspace > > Hi, > > > Instead of delivering page flip events, we choose to post display > > vblank event. Handling page flip events for both primary plane and > > cursor plane may make user space quite busy, although we have the > > mask/unmask mechansim for mitigation. Besides, there are some cases > > that guest app only uses one framebuffer for both drawing and display. > > In such case, guest OS won't do the plane page flip when the > > framebuffer is updated, thus the user land won't be notified about the > updated framebuffer. > > What happens when the guest is idle and doesn't draw anything to the > framebuffer? The vblank event will be delivered to userspace as well, unless guest OS disable the pipe. Does it make sense to vfio/display? Thanks. BR, Tina > > cheers, > Gerd
