Issue with Intel UNDI, PXE-2.1 (build 083) @ Realtek PCIe GBE v2.31 @ Asus P7H55-M LX

[harryc]

A new update to an old problem. Machine details below.

When using ipxe.ipxe and undionly.kpxe sanbooting windows takes over an hour. Seemingly randomly it can take 'only' about ten minutes.
However, using 10ec8168.kpxe it takes around 3 minutes. Variables uninitialized before use?

More interesting is: When windows does finally boot and the vendor provided net driver takes over: Full speed and normal operations occur.

Notice that the routine realtek_detect makes no use of the pci device id, rather it writes and then reads back device control registers trying to deduce the info the vendor, product and rev info already makes clear. My guess is these read/write cycles set reserved bits on chips not designed to have them written, leading them into the weeds, or possibly corrupting device data structures such as bytes/transfer or latency settings.

There was observations on other threads that the device line speed was corrupted by this driver leading to 10 mb operations. I don't see that here, at least to the extent the switch reports a steady line speed of 1GB/s

FYI at https://pci-ids.ucw.cz/read/PC/10ec/8168 we have:
The exact name depends on the revision ID. The rev id + name are shown below:
01 8168B (driver known as 8168)
02 8168C
03 8168D
04 8168DP
06 8168E
07 8168F (same driver as 8168E?), succesors: 0B 0C 0D 0E 0F 10
08 8168ES
09 8168FB (same driver as 8168E?)
0A 8411 (same driver as 8168E?)

Source: Netrtle.inf from a Realtek PCIe LAN driver at http://download.gigabyte.eu/FileList/Dri...k_8111.exe

And: RTL8111GR has same 10ec:8168 but its revision is 11
Source is lspci and eyes (chip name is also written in motherboard specification)
sudo lspci -nnkvv -s 03:00.0
03:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 11)
Subsystem: ASUSTeK Computer Inc. Device [1043:859e]

The machine, an old: Gigabyte Technology Co., Ltd. P35-DQ6/P35-DQ6, BIOS F9 06/22/2009
with an onboard: 04:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 01)
Subsystem: Gigabyte Technology Co., Ltd Motherboard [1458:e000]
Flags: bus master, fast devsel, latency 0, IRQ 45
I/O ports at c000 [size=256]
Memory at f0000000 (64-bit, non-prefetchable) [size=4K]
[virtual] Expansion ROM at f8400000 [disabled] [size=64K]
Capabilities: [40] Power Management version 2
Capabilities: [48] Vital Product Data
Capabilities: [50] MSI: Enable+ Count=1/2 Maskable- 64bit+
Capabilities: [60] Express Endpoint, MSI 00
Capabilities: [84] Vendor Specific Information: Len=4c <?>
Capabilities: [100] Advanced Error Reporting
Capabilities: [12c] Virtual Channel
Capabilities: [148] Device Serial Number 25-00-00-00-10-ec-81-68
Capabilities: [154] Power Budgeting <?>
Kernel driver in use: r8169