> From: Olaf Hering > Sent: Thursday, February 21, 2013 10:53 AM > To: Haiyang Zhang > Cc: FlorianSchandinat@xxxxxx; linux-fbdev@xxxxxxxxxxxxxxx; KY Srinivasan; jasowang@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer Driver > > On Tue, Feb 19, Haiyang Zhang wrote: > > > In my test, the vesafb doesn't automatically give up the emulated video device, > > unless I add the DMI based mechanism to let it exit on Hyper-V. > > From reading the code, it seems to do that via > do_remove_conflicting_framebuffers(). hypervfb does not set apertures > etc, so that function is a noop. We are currently allocating a new framebuffer for hyperv_fb, which is different from the framebuffer for the emulated video. So this cannot be detected by do_remove_conflicting_framebuffers() based on apertures_overlap(). > My point is that with this new driver distro kernel will have no console > output until hypervfb is loaded. On native hardware there is at least > vesafb which can display something until initrd is running. So if the > hypervisor allows that hypervfb can shutdown the emulated vesa hardware > then it should do that. Since the generic vga driver starts to work early in the boot process, the console messages are still displayed without vesafb. Actually, I didn't see any console messages missing when comparing it to the original VM before my patch. Thanks, - Haiyang _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
