Re: [edk2-devel] [PATCH 1/1] OvmfPkg PlatformBootManagerLib: Move TryRunningQemuKernel()

["Gerd Hoffmann" <kraxel@redhat.com>]

  Hi,

> > -drive file=disk.img,format=raw,cache=none,index=0,media=disk \
> > -cdrom
> > /storage/iso/slackware/slackware64-15.0/slackware64-15.0-20210807.iso 
> 
> There's no definition of a disk device in here.

First line is disk, second is cdrom.  Both are attached to the piix4 ide
controller.

Linux finds the controller just fine in both cases (see bugzilla for
the logs):

	ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc040 irq 14
	ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc048 irq 15

But only in one case it finds disk and cdrom:

	ata1.00: ATA-7: QEMU HARDDISK, 2.5+, max UDMA/100
	ata1.00: 41943040 sectors, multi 16: LBA48 
	ata2.00: ATAPI: QEMU DVD-ROM, 2.5+, max UDMA/100
	[ ... ]

Not obvious why.  There isn't an error message in the non-working case.
Does ovmf talk to the ide controller in case the order of the two calls
is changed?  Maybe that does some initialization which the linux driver
depends on.

take care,
  Gerd