> -----Original Message----- > From: Olaf Hering [mailto:o...@aepfle.de] > Sent: Tuesday, February 19, 2013 11:51 AM > To: Haiyang Zhang > Cc: florianschandi...@gmx.de; linux-fb...@vger.kernel.org; KY Srinivasan; > jasow...@redhat.com; linux-kernel@vger.kernel.org; > de...@linuxdriverproject.org > Subject: Re: [PATCH RFC] video: Add Hyper-V Synthetic Video Frame Buffer > Driver > > On Fri, Feb 15, Haiyang Zhang wrote: > > > @@ -508,6 +544,18 @@ static int __init vesafb_init(void) > > int ret; > > char *option = NULL; > > > > +#if IS_ENABLED(CONFIG_HYPERV_FB) > > + /* > > + * On Hyper-V both the emulated and synthetic video devices are > > + * available. To avoid conflicts, we disable vesafb for the > emulated > > + * video if hyperv_fb is configured. > > + */ > > + if (is_hyperv()) { > > + pr_info("Disabled vesafb on Hyper-V.\n"); > > + return -ENODEV; > > + } > > +#endif > > What is the reason for this hook? Is it not possible to claim the > display like its appearently done by other drivers (like radeonfb can > take over display from vesafb)?
The emulated video device is a separate device from the synthetic video. The synthetic driver can only take control of the synthetic video, but not the emulated video. Actually, we already have a similar mechanism in ata/ata_piix.c to disable emulated IDE drive on Hyper-V, so it won't conflict with the synthetic drive. Thanks, - Haiyang
