On Wed, 26 May 2021 at 15:55, Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote: > > Hi Ard, > > Am 25.05.21 um 19:18 schrieb Ard Biesheuvel: > > [SNIP] > >>> I seriously doubt that this is what is going on here. > >>> > >>> lspci -x will give you the bare BAR values - I suspect that those are > >>> probably fine. > >> lspci -x > >> 00:00.0 PCI bridge: Fuzhou Rockchip Electronics Co., Ltd Device 3566 (rev 01) > >> 00: 87 1d 66 35 07 05 10 40 01 00 04 06 00 00 01 00 > >> 10: 00 00 00 00 00 00 00 00 00 01 ff 00 10 10 00 20 > >> 20: 00 10 00 10 01 00 f1 0f 00 00 00 00 00 00 00 00 > >> 30: 00 00 00 00 40 00 00 00 00 00 00 00 5f 01 02 00 > >> > >> 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. > >> [AMD/ATI] Turks PRO [Radeon HD 7570] > >> 00: 02 10 5d 67 07 00 10 20 00 00 00 03 00 00 80 00 > >> 10: 0c 00 00 00 00 00 00 00 > > This is a 64-bit prefetchable BAR programmed with bus address 0x0 > > > >> 04 00 00 10 00 00 00 00 > > This is a 64-bit non-prefetchable BAR programmed with bus address 0x1000_0000 > > > > (https://en.wikipedia.org/wiki/PCI_configuration_space describes the > > meaning of the low order BAR bits) > > Sorry for jumping into the middle of the discussion and to be honest I > haven't fully read it. > > This looks a bit odd since on AMD VGA hardware the non-prefetchable BAR > is usually only 32bit, not 64bit. > > But this hardware generation is rather old and I'm not sure what the BAR > assignment for that generation was. I would need to dig up the register > description in our archives as well. > I have another museum piece in my AMD Seattle: 02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Oland XT [Radeon HD 8670 / R7 250/350] (rev 81) (prog-if 00 [VGA controller]) Subsystem: Dell Oland XT [Radeon HD 8670 / R7 250/350] Flags: bus master, fast devsel, latency 0, IRQ 255 Memory at 100000000 (64-bit, prefetchable) [size=4G] Memory at 40000000 (64-bit, non-prefetchable) [size=256K] I/O ports at 1000 [disabled] [size=256] Expansion ROM at 40060000 [disabled] [size=128K] Capabilities: <access denied> Kernel modules: radeon, amdgpu So AMD/ATI ASICs definitely exist that expose a 64-bit pref and a 64-bit non-pref BAR. -- Ard.
