On 10/01/12 22:16, Andrew Fish wrote: > > On Oct 1, 2012, at 11:08 AM, Laszlo Ersek wrote:
>> Or maybe I mis-attributed the blame to grub_efi_set_text_mode()... Yes, I think I was wrong about it. "Welcome to GRUB!" is printed after grub_machine_init() (and hence grub_efi_set_text_mode()) returns. I recall one occasion when I started the guest right after host boot, and the guest boot was slow enough that I could read the welcome banner correctly rendered for a split second. So whatever distorts the screen comes after the welcome message, and thus it can't be called fom grub_machine_init(). > I was guessing it was just a bug in grub if > EFI_CONSOLE_CONTROL_PROTOCOL was not implemented on a platform as the > screen behavior is different in the two cases: > 1) EFI_CONSOLE_CONTROL_PROTOCOL in graphics mode > Writes to the EFI console do not go to the graphics screen , but > writes to non-graphics consoles still go through. > 2) No EFI_CONSOLE_CONTROL_PROTOCOL > All writes go through to the graphics screen at all times. > > The other question is the "glitch" text being drawn to the screen? It looks like <http://people.redhat.com/~lersek/Screenshot-fw-ovmf.g-f18xfcealpha.e-rhel63%20Virtual%20Machine.png>. The text with the highlighted background is "Welcome to GRUB!" > If > so then it could be related to EFI_CONSOLE_CONTROL_PROTOCOL not being > present. The other thing that can cause glitches is mode changes, so > look for calls to EFI_GRAPHICS_OUTPUT_PROTOCOL.SetMode() in Grub for > that. Yes, I think it's case (2) and we'll probably have to look for the problem elsewhere. > I also wonder if the "glitches" look worse on QEMU as the graphics > speeds could be slower than a real platform? I have only seen it on qemu. Although I didn't look elsewhere, I think it doesn't apply to real hardware -- people test grub2-efi on real hardware regularly, and I think the problem would have been caught / fixed there already. Thanks! Laszlo ------------------------------------------------------------------------------ Got visibility? Most devs has no idea what their production app looks like. Find out how fast your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219671;13503038;y? http://info.appdynamics.com/FreeJavaPerformanceDownload.html _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
