> On 18-Feb-2023, at 6:50 PM, Orlando Chamberlain <orlandoch.dev@xxxxxxxxx> wrote: > Hi All, > This patch series adds support for the MMIO based gmux present on these > Dual GPU Apple T2 Macs: MacBookPro15,1, MacBookPro15,3, MacBookPro16,1, > MacBookPro16,4 (although amdgpu isn't working on MacBookPro16,4 [1]). > Could be an upstream bug, but I’ve noticed that after using these patches, if I add `acpi_backlight=video` in the command line, it still uses `gmux_backlight` Hans, any ideas why? > Changes from v2[2]: > > - Add "," to last item in apple_gmux_type enum > - Don't not clear interrupts when status is 0 > - Don't check if we failed to make debugfs folder > - Check for fake mmio gmux > > # 1: > > has a slight change in how the switch state is read: instead of checking > for x == 2, check !(x & 1) > > # 2: > > implements a system to support more than 2 gmux types > > # 3: > > start using the gmux's GMSP acpi method when handling interrupts on MMIO > gmux's. This is needed for the MMIO gmux's to clear interrupts. > > # 4: > > Adds support for the MMIO based gmux on T2 macs. > > # 5: > > Add a debugfs interface to apple-gmux so data from ports can be read > and written to from userspace. > > This can be used for more easily researching what unknown ports do, > and switching gpus when vga_switcheroo isn't ready (e.g. when one gpu > is bound to vfio-pci and in use by a Windows VM, I can use this to > switch my internal display between Linux and Windows easily). > > # Issues: > > 1. Switching gpus at runtime has the same issue as indexed gmux's: the > inactive gpu can't probe the DDC lines for eDP [3] > > 2. iMacPro1,1, iMac20,1 and iMac20,2 all seem to have a gmux in their > acpi tables, but they shouldn't. A check that hopefully will detect this > is used, but it's untested as I don't have any of those computers. > > 3. Powering on the amdgpu with vga_switcheroo doesn't work well. I'm > told on the MacBookPro15,1 it works sometimes, and adding delays helps, > but on my MacBookPro16,1 I haven't been able to get it to work at all: > > amdgpu: switched off > amdgpu: switched on > amdgpu 0000:03:00.0: > Unable to change power state from D3hot to D0, device inaccessible > amdgpu 0000:03:00.0: > Unable to change power state from D3cold to D0, device inaccessible > [drm] PCIE GART of 512M enabled (table at 0x00000080FEE00000). > [drm] PSP is resuming... > [drm:psp_hw_start [amdgpu]] *ERROR* PSP create ring failed! > [drm:psp_resume [amdgpu]] *ERROR* PSP resume failed > [drm:amdgpu_device_fw_loading [amdgpu]] > *ERROR* resume of IP block <psp> failed -62 > amdgpu 0000:03:00.0: amdgpu: amdgpu_device_ip_resume failed (-62). > snd_hda_intel 0000:03:00.1: Enabling via vga_switcheroo > snd_hda_intel 0000:03:00.1: > Unable to change power state from D3cold to D0, device inaccessible > snd_hda_intel 0000:03:00.1: CORB reset timeout#2, CORBRP = 65535 > snd_hda_codec_hdmi hdaudioC0D0: Unable to sync register 0x2f0d00. -5 > > There are some acpi methods (PWRD, PWG1 [4, 5]) that macOS calls when > changing the amdgpu's power state, but we don't use them and that could be > a cause. Additionally unlike previous generation Macbooks which work > better, on MacBookPro16,1 the gpu is located behind 2 pci bridges: > > 01:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] > Navi 10 XL Upstream Port of PCI Express Switch (rev 43) > 02:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] > Navi 10 XL Downstream Port of PCI Express Switch > 03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] > Navi 14 [Radeon RX 5500/5500M / Pro 5500M] (rev 43) > 03:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] > Navi 10 HDMI Audio > > Upon attempting to power on the gpu with vga_switcheroo, all these > devices except 01:00.0 have their config space filled with 1s. > Rescanning pci makes the config space of all the devices go back to > normal, however amdgpu still fails to resume with the same logs as > above. > > [1]: https://lore.kernel.org/all/3AFB9142-2BD0-46F9-AEA9-C9C5D13E68E6@xxxxxxxx/ > [2]: https://lore.kernel.org/platform-driver-x86/20230216122342.5918-1-orlandoch.dev@xxxxxxxxx/ > [3]: https://lore.kernel.org/all/9eed8ede6f15a254ad578e783b050e1c585d5a15.1439288957.git.lukas@xxxxxxxxx/ > [4]: https://gist.github.com/Redecorating/6c7136b7a4ac7ce3b77d8e41740dd87b > [5]: https://lore.kernel.org/all/20120710160555.GA31562@xxxxxxxxxxxxx/ > > Orlando Chamberlain (5): > apple-gmux: use first bit to check switch state > apple-gmux: refactor gmux types > apple-gmux: Use GMSP acpi method for interrupt clear > apple-gmux: support MMIO gmux on T2 Macs > apple-gmux: add debugfs interface > > drivers/platform/x86/apple-gmux.c | 349 ++++++++++++++++++++++++++---- > include/linux/apple-gmux.h | 70 ++++-- > 2 files changed, 357 insertions(+), 62 deletions(-) > > -- > 2.39.1
