Messages in this thread | | | Date | Tue, 9 Aug 2022 13:55:05 +0300 | From | Mika Westerberg <> | Subject | Re: Apple Thunderbolt Display chaining |
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Hi,
On Tue, Aug 09, 2022 at 06:40:54PM +0800, Brad Campbell wrote: > G'day Mika, > > > On 9/8/22 18:23, Mika Westerberg wrote: > > Hi, > > > > On Mon, Aug 08, 2022 at 09:27:24PM +0800, Brad Campbell wrote: > >> If I don't authorize the PCIe tunnels and just leave the DP enabled it > >> works fine also. > > > > But you say that it fails on boot when the driver discovers the tunnels, > > right? So there is really nothing to authorize (they should be already > > "authorized" by the boot firmware). > > > > If I understand correctly this is how it reproduces (the simplest): > > > > 1. Connect a single Apple TB1 display to the system > > 2. Boot it up > > 3. Wait a while and it hangs > > > > If this is the case, then the driver certainly is not creating any > > PCIe tunnels itself unless there is a bug somewhere. > > > > An additional question, does it reproduce with either TB1 display > > connected or just with specific TB1 display? > > > > No, I've not been clear enough, I'm sorry. I've re-read what I've written below and > I'm still not sure I'm clear enough. > > The firmware never sets anything up. > > When I cold boot the machine (from power on), the thunderbolt displays and tunnels > remain dark until linux initializes the thunderbolt driver the first time. > > If I compile the thunderbolt driver into the kernel, or let the initramfs load it > the displays come up, all PCIe tunnels are established and everything works. > > When I reboot the machine (reset button or warm boot), the firmware continues to > do nothing and all the tunnels remain in place. The machine dies when the thunderbolt > driver is loaded for a second time. > > That might be a reset/warm boot with it compiled in or loaded from iniramfs. > It may also be me loading it from the command line after booting with it as a > module and blacklisted. > > The problem comes about when the thunderbolt module is loaded while the PCIe tunnels > are already established. > > To reproduce in the easiest manner I compile the thunderbolt driver as a module and > blacklist it. This prevents it from auto-loading. > > I cold boot the machine, let it boot completely then modprobe thunderbolt and authorize > the tunnels. I then warm boot which lets the kernel detect and init the DP displays > and detect/configure all the PCIe devices. The thunderbolt driver is not loaded. > > The machine comes up, all tunnels are established and all devices work. > > If I then modprobe the thunderbolt driver, things break. > > This is the hack in my boot script : > > # Spark up thunderbolt > if [ -z "`grep notb /proc/cmdline`" -a -z "`lsusb | grep '05ac:9227'`" ] ; then > modprobe thunderbolt > sleep 1 > echo 1 > /sys/bus/thunderbolt/devices/0-3/authorized > echo 1 > /sys/bus/thunderbolt/devices/0-303/authorized > reboot > fi
Thanks for the clarification! How about on macOS side, does it work (I would expect yes)?
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