Re: [Intel-gfx] A panic and a hang in the i915 drm driver
On Mon, 08 Jun 2020, David Howells wrote: > Jani Nikula wrote: > >> David, please try [1]. > > Assuming you mean this: > > https://patchwork.freedesktop.org/patch/366958/?series=77635=1 > > yes, that works. > > Tested-by: David Howells Many thanks, Jani. -- Jani Nikula, Intel Open Source Graphics Center ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] A panic and a hang in the i915 drm driver
Jani Nikula wrote: > David, please try [1]. Assuming you mean this: https://patchwork.freedesktop.org/patch/366958/?series=77635=1 yes, that works. Tested-by: David Howells ___ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Re: [Intel-gfx] A panic and a hang in the i915 drm driver
HI,
> -Original Message-
> From: Intel-gfx On Behalf Of Jani
> Nikula
> Sent: maanantai 8. kesäkuuta 2020 10.49
> To: David Howells ; Joonas Lahtinen
> ; Vivi, Rodrigo
> Cc: intel-gfx@lists.freedesktop.org; linux-ker...@vger.kernel.org; dri-
> de...@lists.freedesktop.org; dhowe...@redhat.com; airl...@redhat.com
> Subject: Re: [Intel-gfx] A panic and a hang in the i915 drm driver
>
> On Sun, 07 Jun 2020, David Howells wrote:
> > Hi,
> >
> > I'm seeing the attached oops and panic from the i915 drm driver. I've tried
> > bisecting it, but there's a problem in that one of the merged branches
> > causes
> > the machine to hang without output.
It was not this one?
https://gitlab.freedesktop.org/drm/intel/-/issues/1892
>
> Cc: Ville and GG, I thought this was fixed (reverted) already.
>
> BR,
> Jani.
>
>
> >
> > The oops for commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 looks like:
> >
> > BUG: kernel NULL pointer dereference, address:
> > #PF: supervisor read access in kernel mode
> > #PF: error_code(0x) - not-present page
> > PGD 0 P4D 0
> > Oops: [#1] SMP PTI
> > CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc2-fscache+ #883
> > Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
> > RIP: 0010:intel_psr_enabled+0xb/0x6e
> > Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4
> > 10 5b 5d
> 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff f6 83
> 5e 08 00
> 00 20 75 05 45 31 e4 eb 44 80
> > RSP: :88840dedfa18 EFLAGS: 00010246
> > RAX: RBX: 8884086f9000 RCX:
> > RDX: 0001 RSI: 8884086f9000 RDI: 0128
> > RBP: 8884086fb000 R08: R09: 0001
> > R10: 0001 R11: 00ff R12: 88840868
> > R13: R14: R15: 8884086fb200
> > FS: () GS:88840fb0()
> knlGS:
> > CS: 0010 DS: ES: CR0: 80050033
> > CR2: CR3: 0440c001 CR4: 001606e0
> > Call Trace:
> > intel_read_dp_sdp+0x71/0x2c5
> > hsw_crt_get_config+0x18/0x41
> > intel_modeset_readout_hw_state+0x24d/0x662
> > ? do_raw_spin_lock+0x8b/0xcd
> > ? _raw_spin_lock_irqsave+0x10/0x16
> > intel_modeset_setup_hw_state+0xa8/0xb59
> > ? __next_node_in+0x39/0x42
> > ? ww_mutex_lock+0x3d/0x1da
> > ? modeset_lock+0xd4/0x114
> > ? drm_modeset_lock_all_ctx+0x86/0xcc
> > intel_modeset_init+0x285/0x5bf
> > ? intel_irq_postinstall+0x485/0x4d1
> > i915_driver_probe+0x1b4/0x49c
> > ? __kernfs_new_node+0x161/0x1b2
> > ? rpm_resume+0x45e/0x485
> > i915_pci_probe+0xfd/0x11d
> > ? __pm_runtime_resume+0x51/0x5e
> > local_pci_probe+0x39/0x7a
> > pci_device_probe+0xf5/0x14f
> > ? sysfs_do_create_link_sd.isra.0+0x77/0xa3
> > really_probe+0x140/0x2a9
> > driver_probe_device+0x9c/0xd1
> > device_driver_attach+0x3c/0x55
> > __driver_attach+0x97/0x9f
> > ? device_driver_attach+0x55/0x55
> > bus_for_each_dev+0x72/0xa8
> > bus_add_driver+0x108/0x1b9
> > driver_register+0x9e/0xd7
> > ? mipi_dsi_bus_init+0x11/0x11
> > i915_init+0x58/0x6b
> > do_one_initcall+0x83/0x18a
> > kernel_init_freeable+0x19b/0x1fd
> > ? rest_init+0x9f/0x9f
> > kernel_init+0xa/0xfa
> > ret_from_fork+0x1f/0x30
> > Modules linked in:
> > CR2:
> > ---[ end trace d0c4f561618aeb37 ]---
> > RIP: 0010:intel_psr_enabled+0xb/0x6e
> > Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4
> > 10 5b 5d
> 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff f6 83
> 5e 08 00
> 00 20 75 05 45 31 e4 eb 44 80
> > RSP: :88840dedfa18 EFLAGS: 00010246
> > RAX: RBX: 8884086f9000 RCX:
> > RDX: 0001 RSI: 8884086f9000 RDI: 0128
> > RBP: 8884086fb000 R08: R09: 0001
> > R10: 0001 R11: 00ff R12: 88840868
> > R13: R14: R15: 8884086fb200
> > FS: () GS:88840fb0()
> knlGS:
> > CS: 0010 DS: ES: CR0: 80050033
> > CR2: CR3: 0440c001 CR4: 001606e0
> > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0009
> > Kernel Offset: disabled
> > ---[ end Kernel panic - not syncing: Attempted to kill init!
> > exitcode=0x0009 ]---
> >
> >
> > Decoding the RIP gives:
> >
> > RIP: 0010:intel_psr_enabled (/data/fs/linux-
> fs/build3/../drivers/gpu/drm/i915/display/intel_display_types.h:1595
> /data/fs/linux-
> fs/build3/../drivers/gpu/drm/i915/display/intel_psr.c:1598)
> >
> >
> >
> > Commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 ("Merge tag
> > 'drm-intel-next-fixes-2020-05-20' of
> > git://anongit.freedesktop.org/drm/drm-intel into drm-next") is definitely
> > bad
> > and logs an oops to the console and panics, but it's
Re: [Intel-gfx] A panic and a hang in the i915 drm driver
On Sun, 07 Jun 2020, David Howells wrote:
> Hi,
>
> I'm seeing the attached oops and panic from the i915 drm driver. I've tried
> bisecting it, but there's a problem in that one of the merged branches causes
> the machine to hang without output.
Cc: Ville and GG, I thought this was fixed (reverted) already.
BR,
Jani.
>
> The oops for commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 looks like:
>
> BUG: kernel NULL pointer dereference, address:
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x) - not-present page
> PGD 0 P4D 0
> Oops: [#1] SMP PTI
> CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc2-fscache+ #883
> Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
> RIP: 0010:intel_psr_enabled+0xb/0x6e
> Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4 10
> 5b 5d 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff
> f6 83 5e 08 00 00 20 75 05 45 31 e4 eb 44 80
> RSP: :88840dedfa18 EFLAGS: 00010246
> RAX: RBX: 8884086f9000 RCX:
> RDX: 0001 RSI: 8884086f9000 RDI: 0128
> RBP: 8884086fb000 R08: R09: 0001
> R10: 0001 R11: 00ff R12: 88840868
> R13: R14: R15: 8884086fb200
> FS: () GS:88840fb0() knlGS:
> CS: 0010 DS: ES: CR0: 80050033
> CR2: CR3: 0440c001 CR4: 001606e0
> Call Trace:
> intel_read_dp_sdp+0x71/0x2c5
> hsw_crt_get_config+0x18/0x41
> intel_modeset_readout_hw_state+0x24d/0x662
> ? do_raw_spin_lock+0x8b/0xcd
> ? _raw_spin_lock_irqsave+0x10/0x16
> intel_modeset_setup_hw_state+0xa8/0xb59
> ? __next_node_in+0x39/0x42
> ? ww_mutex_lock+0x3d/0x1da
> ? modeset_lock+0xd4/0x114
> ? drm_modeset_lock_all_ctx+0x86/0xcc
> intel_modeset_init+0x285/0x5bf
> ? intel_irq_postinstall+0x485/0x4d1
> i915_driver_probe+0x1b4/0x49c
> ? __kernfs_new_node+0x161/0x1b2
> ? rpm_resume+0x45e/0x485
> i915_pci_probe+0xfd/0x11d
> ? __pm_runtime_resume+0x51/0x5e
> local_pci_probe+0x39/0x7a
> pci_device_probe+0xf5/0x14f
> ? sysfs_do_create_link_sd.isra.0+0x77/0xa3
> really_probe+0x140/0x2a9
> driver_probe_device+0x9c/0xd1
> device_driver_attach+0x3c/0x55
> __driver_attach+0x97/0x9f
> ? device_driver_attach+0x55/0x55
> bus_for_each_dev+0x72/0xa8
> bus_add_driver+0x108/0x1b9
> driver_register+0x9e/0xd7
> ? mipi_dsi_bus_init+0x11/0x11
> i915_init+0x58/0x6b
> do_one_initcall+0x83/0x18a
> kernel_init_freeable+0x19b/0x1fd
> ? rest_init+0x9f/0x9f
> kernel_init+0xa/0xfa
> ret_from_fork+0x1f/0x30
> Modules linked in:
> CR2:
> ---[ end trace d0c4f561618aeb37 ]---
> RIP: 0010:intel_psr_enabled+0xb/0x6e
> Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4 10
> 5b 5d 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff
> f6 83 5e 08 00 00 20 75 05 45 31 e4 eb 44 80
> RSP: :88840dedfa18 EFLAGS: 00010246
> RAX: RBX: 8884086f9000 RCX:
> RDX: 0001 RSI: 8884086f9000 RDI: 0128
> RBP: 8884086fb000 R08: R09: 0001
> R10: 0001 R11: 00ff R12: 88840868
> R13: R14: R15: 8884086fb200
> FS: () GS:88840fb0() knlGS:
> CS: 0010 DS: ES: CR0: 80050033
> CR2: CR3: 0440c001 CR4: 001606e0
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x0009
> Kernel Offset: disabled
> ---[ end Kernel panic - not syncing: Attempted to kill init!
> exitcode=0x0009 ]---
>
>
> Decoding the RIP gives:
>
> RIP: 0010:intel_psr_enabled
> (/data/fs/linux-fs/build3/../drivers/gpu/drm/i915/display/intel_display_types.h:1595
> /data/fs/linux-fs/build3/../drivers/gpu/drm/i915/display/intel_psr.c:1598)
>
>
>
> Commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 ("Merge tag
> 'drm-intel-next-fixes-2020-05-20' of
> git://anongit.freedesktop.org/drm/drm-intel into drm-next") is definitely bad
> and logs an oops to the console and panics, but it's a merge.
>
> On one side is e20bb857dea2f620ff37ae541ed8aee70e3c89f1 ("Merge tag
> 'exynos-drm-next-for-v5.8' of
> git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into
> drm-next"), which hangs. This is also a merge.
>
> One side of e20bb is f84e1ba336a4f47ae251e4d2d8a694902571b0df
> ("drm/exynos-vidi: convert platform driver to use dev_groups") which is good.
>
> The other side of c4121 and e20bb derive from the same line of commits, with
> three patches between. All of these, down to at least
> 230982d8d8df7f9d9aa216840ea2db1df6ad5d37 ("drm/i915: Update DRIVER_DATE to
> 20200430") cause the machine to hang without any sort of console output.
>
> Commit
Re: [Intel-gfx] A panic and a hang in the i915 drm driver
Here's the dmesg from a successful boot (commit f84e1ba336a4f47ae251e4d2d8a694902571b0df). David --- [0.007455] Normal [mem 0x0001-0x00041fdf] [0.007456] Movable zone start for each node [0.007456] Early memory node ranges [0.007457] node 0: [mem 0x1000-0x00057fff] [0.007458] node 0: [mem 0x00059000-0x0009efff] [0.007459] node 0: [mem 0x0010-0xaf304fff] [0.007460] node 0: [mem 0xaf30c000-0xaf774fff] [0.007460] node 0: [mem 0xafbbd000-0xd8b7bfff] [0.007461] node 0: [mem 0xd9fff000-0xd9ff] [0.007461] node 0: [mem 0x0001-0x00041fdf] [0.007845] Zeroed struct page in unavailable ranges: 31541 pages [0.007846] Initmem setup node 0 [mem 0x1000-0x00041fdf] [0.007848] On node 0 totalpages: 4162763 [0.007849] DMA zone: 64 pages used for memmap [0.007849] DMA zone: 24 pages reserved [0.007850] DMA zone: 3997 pages, LIFO batch:0 [0.007901] DMA32 zone: 13789 pages used for memmap [0.007901] DMA32 zone: 882478 pages, LIFO batch:63 [0.020153] Normal zone: 51192 pages used for memmap [0.020155] Normal zone: 3276288 pages, LIFO batch:63 [0.064070] Reserving Intel graphics memory at [mem 0xdb20-0xdf1f] [0.064144] ACPI: PM-Timer IO Port: 0x1808 [0.064146] ACPI: Local APIC address 0xfee0 [0.064150] ACPI: LAPIC_NMI (acpi_id[0xff] high edge lint[0x1]) [0.064159] IOAPIC[0]: apic_id 8, version 32, address 0xfec0, GSI 0-23 [0.064161] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl) [0.064162] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level) [0.064163] ACPI: IRQ0 used by override. [0.064164] ACPI: IRQ9 used by override. [0.064166] Using ACPI (MADT) for SMP configuration information [0.064167] ACPI: HPET id: 0x8086a701 base: 0xfed0 [0.064171] [Firmware Bug]: TSC_DEADLINE disabled due to Errata; please update microcode to version: 0x22 (or later) [0.064172] smpboot: Allowing 4 CPUs, 0 hotplug CPUs [0.064198] [mem 0xdf20-0xf7ff] available for PCI devices [0.064204] clocksource: refined-jiffies: mask: 0x max_cycles: 0x, max_idle_ns: 7645519600211568 ns [0.077227] setup_percpu: NR_CPUS:4 nr_cpumask_bits:4 nr_cpu_ids:4 nr_node_ids:1 [0.077563] percpu: Embedded 54 pages/cpu s181200 r8192 d31792 u524288 [0.077569] pcpu-alloc: s181200 r8192 d31792 u524288 alloc=1*2097152 [0.077570] pcpu-alloc: [0] 0 1 2 3 [0.077588] Built 1 zonelists, mobility grouping on. Total pages: 4097694 [0.077588] Policy zone: Normal [0.077590] Kernel command line: BOOT_IMAGE=/data/tftp/andromeda-vmlinuz ip=enp3s0:dhcp console=tty0 console=ttyS0,115200 ro root=/dev/sdb2 [0.079327] Dentry cache hash table entries: 2097152 (order: 12, 16777216 bytes, linear) [0.080136] Inode-cache hash table entries: 1048576 (order: 11, 8388608 bytes, linear) [0.080167] mem auto-init: stack:off, heap alloc:off, heap free:off [0.159182] Memory: 16016000K/16651052K available (12290K kernel code, 1927K rwdata, 5372K rodata, 1608K init, 1296K bss, 635052K reserved, 0K cma-reserved) [0.159242] Kernel/User page tables isolation: enabled [0.159256] ftrace: allocating 47297 entries in 185 pages [0.172236] ftrace: allocated 185 pages with 5 groups [0.172293] rcu: Hierarchical RCU implementation. [0.172294] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies. [0.175046] NR_IRQS: 4352, nr_irqs: 456, preallocated irqs: 16 [0.175193] rcu: Offload RCU callbacks from CPUs: (none). [0.175244] random: get_random_bytes called from start_kernel+0x3f5/0x5c0 with crng_init=0 [0.175342] Console: colour dummy device 80x25 [0.175458] printk: console [tty0] enabled [0.957870] printk: console [ttyS0] enabled [0.960753] ACPI: Core revision 20200326 [0.963468] clocksource: hpet: mask: 0x max_cycles: 0x, max_idle_ns: 133484882848 ns [0.971296] APIC: Switch to symmetric I/O mode setup [0.975260] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=0 pin2=0 [0.999294] clocksource: tsc-early: mask: 0x max_cycles: 0x6a6cab8f549, max_idle_ns: 881590883366 ns [1.008503] Calibrating delay loop (skipped), value calculated using timer frequency.. 7383.19 BogoMIPS (lpj=14766392) [1.012503] pid_max: default: 32768 minimum: 301 [1.024069] LSM: Security Framework initializing [1.024510] Yama: becoming mindful. [1.028507] SELinux: Initializing. [1.030772] Mount-cache hash table entries: 32768 (order: 6, 262144 bytes, linear) [1.032558] Mountpoint-cache hash table entries: 32768 (order: 6, 262144 bytes, linear) [1.036710] mce: CPU0: Thermal monitoring enabled (TM1) [1.040511] process: using mwait in idle threads [
[Intel-gfx] A panic and a hang in the i915 drm driver
Hi,
I'm seeing the attached oops and panic from the i915 drm driver. I've tried
bisecting it, but there's a problem in that one of the merged branches causes
the machine to hang without output.
The oops for commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 looks like:
BUG: kernel NULL pointer dereference, address:
#PF: supervisor read access in kernel mode
#PF: error_code(0x) - not-present page
PGD 0 P4D 0
Oops: [#1] SMP PTI
CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc2-fscache+ #883
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
RIP: 0010:intel_psr_enabled+0xb/0x6e
Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4 10
5b 5d 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff f6
83 5e 08 00 00 20 75 05 45 31 e4 eb 44 80
RSP: :88840dedfa18 EFLAGS: 00010246
RAX: RBX: 8884086f9000 RCX:
RDX: 0001 RSI: 8884086f9000 RDI: 0128
RBP: 8884086fb000 R08: R09: 0001
R10: 0001 R11: 00ff R12: 88840868
R13: R14: R15: 8884086fb200
FS: () GS:88840fb0() knlGS:
CS: 0010 DS: ES: CR0: 80050033
CR2: CR3: 0440c001 CR4: 001606e0
Call Trace:
intel_read_dp_sdp+0x71/0x2c5
hsw_crt_get_config+0x18/0x41
intel_modeset_readout_hw_state+0x24d/0x662
? do_raw_spin_lock+0x8b/0xcd
? _raw_spin_lock_irqsave+0x10/0x16
intel_modeset_setup_hw_state+0xa8/0xb59
? __next_node_in+0x39/0x42
? ww_mutex_lock+0x3d/0x1da
? modeset_lock+0xd4/0x114
? drm_modeset_lock_all_ctx+0x86/0xcc
intel_modeset_init+0x285/0x5bf
? intel_irq_postinstall+0x485/0x4d1
i915_driver_probe+0x1b4/0x49c
? __kernfs_new_node+0x161/0x1b2
? rpm_resume+0x45e/0x485
i915_pci_probe+0xfd/0x11d
? __pm_runtime_resume+0x51/0x5e
local_pci_probe+0x39/0x7a
pci_device_probe+0xf5/0x14f
? sysfs_do_create_link_sd.isra.0+0x77/0xa3
really_probe+0x140/0x2a9
driver_probe_device+0x9c/0xd1
device_driver_attach+0x3c/0x55
__driver_attach+0x97/0x9f
? device_driver_attach+0x55/0x55
bus_for_each_dev+0x72/0xa8
bus_add_driver+0x108/0x1b9
driver_register+0x9e/0xd7
? mipi_dsi_bus_init+0x11/0x11
i915_init+0x58/0x6b
do_one_initcall+0x83/0x18a
kernel_init_freeable+0x19b/0x1fd
? rest_init+0x9f/0x9f
kernel_init+0xa/0xfa
ret_from_fork+0x1f/0x30
Modules linked in:
CR2:
---[ end trace d0c4f561618aeb37 ]---
RIP: 0010:intel_psr_enabled+0xb/0x6e
Code: 8b 44 24 08 65 48 33 04 25 28 00 00 00 74 05 e8 7e ff 97 ff 48 83 c4 10
5b 5d 41 5c 41 5d c3 0f 1f 44 00 00 41 55 41 54 55 53 <48> 8b 9f d8 fe ff ff f6
83 5e 08 00 00 20 75 05 45 31 e4 eb 44 80
RSP: :88840dedfa18 EFLAGS: 00010246
RAX: RBX: 8884086f9000 RCX:
RDX: 0001 RSI: 8884086f9000 RDI: 0128
RBP: 8884086fb000 R08: R09: 0001
R10: 0001 R11: 00ff R12: 88840868
R13: R14: R15: 8884086fb200
FS: () GS:88840fb0() knlGS:
CS: 0010 DS: ES: CR0: 80050033
CR2: CR3: 0440c001 CR4: 001606e0
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0009
Kernel Offset: disabled
---[ end Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0009 ]---
Decoding the RIP gives:
RIP: 0010:intel_psr_enabled
(/data/fs/linux-fs/build3/../drivers/gpu/drm/i915/display/intel_display_types.h:1595
/data/fs/linux-fs/build3/../drivers/gpu/drm/i915/display/intel_psr.c:1598)
Commit c41219fda6e04255c44d37fd2c0d898c1c46abf1 ("Merge tag
'drm-intel-next-fixes-2020-05-20' of
git://anongit.freedesktop.org/drm/drm-intel into drm-next") is definitely bad
and logs an oops to the console and panics, but it's a merge.
On one side is e20bb857dea2f620ff37ae541ed8aee70e3c89f1 ("Merge tag
'exynos-drm-next-for-v5.8' of
git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into
drm-next"), which hangs. This is also a merge.
One side of e20bb is f84e1ba336a4f47ae251e4d2d8a694902571b0df
("drm/exynos-vidi: convert platform driver to use dev_groups") which is good.
The other side of c4121 and e20bb derive from the same line of commits, with
three patches between. All of these, down to at least
230982d8d8df7f9d9aa216840ea2db1df6ad5d37 ("drm/i915: Update DRIVER_DATE to
20200430") cause the machine to hang without any sort of console output.
Commit bfbe1744e4417986419236719922a9a7fda224d1 ("Merge tag
'amd-drm-next-5.8-2020-05-19' of git://people.freedesktop.org/~agd5f/linux
into drm-next") is good.
Commit 47e51832ae93534d872511ba557115722582d94c
("drm/i915/gvt: use context lrc_reg_state for shadow ppgtt override") is good.
I've attached the git log and the config file.
David
git bisect start
