Re: [PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-15 Thread Alex Williamson
On Tue, 14 Jun 2022 10:52:52 +0200 Gerd Hoffmann wrote: > On Mon, Jun 13, 2022 at 03:47:04PM +0200, Laszlo Ersek wrote: > > On 06/12/22 19:32, Kevin Locke wrote: > > > PCI Express devices which use legacy VGA compatibility should be placed > > > on the Root Complex. This simplifies ioport

Re: [PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-15 Thread Gerd Hoffmann
Hi, > I think documenting the issue with VBE registers would be helpful. > Doing so with a recommendation for how to avoid the issue seems even > better. Would a recommendation to attach a device which supports VBE > to the Root Complex if VBE will be used by the guest make sense? Yes. This

Re: [PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-14 Thread Kevin Locke
On Tue, 2022-06-14 at 10:52 +0200, Gerd Hoffmann wrote: >> On 06/12/22 19:32, Kevin Locke wrote: >>> PCI Express devices which use legacy VGA compatibility should be placed >>> on the Root Complex. This simplifies ioport access to VGA registers, >>> which requires use of a special exception bit

Re: [PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-14 Thread Gerd Hoffmann
On Mon, Jun 13, 2022 at 03:47:04PM +0200, Laszlo Ersek wrote: > On 06/12/22 19:32, Kevin Locke wrote: > > PCI Express devices which use legacy VGA compatibility should be placed > > on the Root Complex. This simplifies ioport access to VGA registers, > > which requires use of a special exception

Re: [PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-13 Thread Laszlo Ersek
On 06/12/22 19:32, Kevin Locke wrote: > PCI Express devices which use legacy VGA compatibility should be placed > on the Root Complex. This simplifies ioport access to VGA registers, > which requires use of a special exception bit to work across PCI(e) > bridges. It is also necessary for ioport

[PATCH v2] docs: add PCIe root bus for VGA compat guideline

2022-06-12 Thread Kevin Locke
PCI Express devices which use legacy VGA compatibility should be placed on the Root Complex. This simplifies ioport access to VGA registers, which requires use of a special exception bit to work across PCI(e) bridges. It is also necessary for ioport access to VESA BIOS Extension (VBE) registers,