Hi all

I can confirm this problem on Kubuntu 22.04 LTS for an old Acer Aspire 6930G Laptop and kernel 6.5.0-18-generic. In dmesg I get:

[    4.400118] resource: resource sanity check: requesting [mem 0x00000000000c0000-0x00000000000dffff], which spans more than PCI Bus 0000:00 [mem 0x000d4000-0x000dffff window]
[    4.400124] caller pci_map_rom+0x6c/0x1d0 mapping multiple BARs
[    4.400212] ATOM BIOS: Acer_MXM_B80602_M92XT_DDR2
[    4.400253] radeon 0000:01:00.0: VRAM: 512M 0x0000000000000000 - 0x000000001FFFFFFF (512M used)
[    4.400258] radeon 0000:01:00.0: GTT: 1024M 0x0000000020000000 - 0x000000005FFFFFFF
[    4.400265] [drm] Detected VRAM RAM=512M, BAR=256M
[    4.400267] [drm] RAM width 64bits DDR
[    4.400499] [drm] radeon: 512M of VRAM memory ready
[    4.400503] [drm] radeon: 1024M of GTT memory ready.
[    4.400525] [drm] Loading RV710 Microcode
[    4.401039] ================================================================================
[    4.401047] fbcon: Taking over console
[    4.401055] UBSAN: array-index-out-of-bounds in /build/linux-hwe-6.5-ZV1Qen/linux-hwe-6.5-6.5.0/drivers/gpu/drm/radeon/radeon_atombios.c:2620:43
[    4.401064] index 1 is out of range for type 'UCHAR [1]'
[    4.401069] CPU: 0 PID: 117 Comm: systemd-udevd Not tainted 6.5.0-18-generic #18~22.04.1-Ubuntu
[    4.401073] Hardware name: Acer Aspire 6930G     /Makalu           , BIOS v0.3238 07/28/2009
[    4.401076] Call Trace:
[    4.401079]  <TASK>
[    4.401083]  dump_stack_lvl+0x48/0x70
[    4.401093]  dump_stack+0x10/0x20
[    4.401096]  __ubsan_handle_out_of_bounds+0xc6/0x110
[    4.401103]  radeon_atombios_parse_power_table_4_5+0x3c6/0x3e0 [radeon]
[    4.401289]  radeon_atombios_get_power_modes+0x205/0x210 [radeon]
[    4.401404]  radeon_pm_init_dpm+0x8e/0x2f0 [radeon]
[    4.401550]  radeon_pm_init+0xdf/0x120 [radeon]
[    4.401695]  rv770_init+0x1fa/0x3d0 [radeon]
[    4.401839]  radeon_device_init+0x57e/0xaf0 [radeon]
[    4.401952]  radeon_driver_load_kms+0xcc/0x300 [radeon]
[    4.402066]  drm_dev_register+0x10e/0x240 [drm]
[    4.402187]  radeon_pci_probe+0xec/0x180 [radeon]
[    4.402298]  local_pci_probe+0x47/0xb0
[    4.402304]  pci_call_probe+0x55/0x190
[    4.402308]  pci_device_probe+0x84/0x120
[    4.402313]  really_probe+0x1cc/0x430
[    4.402318]  __driver_probe_device+0x8c/0x190
[    4.402322]  driver_probe_device+0x24/0xd0
[    4.402325]  __driver_attach+0x10b/0x210
[    4.402329]  ? __pfx___driver_attach+0x10/0x10
[    4.402332]  bus_for_each_dev+0x8d/0xf0
[    4.402338]  driver_attach+0x1e/0x30
[    4.402341]  bus_add_driver+0x127/0x240
[    4.402346]  driver_register+0x5e/0x130
[    4.402350]  ? __pfx_radeon_module_init+0x10/0x10 [radeon]
[    4.402461]  __pci_register_driver+0x62/0x70
[    4.402465]  radeon_module_init+0x4c/0xff0 [radeon]
[    4.402575]  do_one_initcall+0x5e/0x340
[    4.402582]  do_init_module+0x68/0x260
[    4.402587]  load_module+0xb85/0xcd0
[    4.402593]  ? security_kernel_post_read_file+0x75/0x90
[    4.402598]  init_module_from_file+0x96/0x100
[    4.402603]  ? init_module_from_file+0x96/0x100
[    4.402609]  idempotent_init_module+0x11c/0x2b0
[    4.402615]  __x64_sys_finit_module+0x64/0xd0
[    4.402620]  do_syscall_64+0x5b/0x90
[    4.402625]  ? generic_file_llseek+0x24/0x40
[    4.402630]  ? ksys_lseek+0x80/0xd0
[    4.402635]  ? exit_to_user_mode_prepare+0x30/0xb0
[    4.402638]  ? syscall_exit_to_user_mode+0x37/0x60
[    4.402643]  ? do_syscall_64+0x67/0x90
[    4.402646]  ? syscall_exit_to_user_mode+0x37/0x60
[    4.402650]  ? do_syscall_64+0x67/0x90
[    4.402654]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[    4.402660] RIP: 0033:0x7ffa446cd88d
[    4.402670] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 b5 0f 00 f7 d8 64 89 01 48
[    4.402673] RSP: 002b:00007ffd4365fd78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[    4.402677] RAX: ffffffffffffffda RBX: 0000556ee8f6ef50 RCX: 00007ffa446cd88d
[    4.402680] RDX: 0000000000000000 RSI: 00007ffa44865441 RDI: 0000000000000014
[    4.402682] RBP: 0000000000020000 R08: 0000000000000000 R09: 0000000000000002
[    4.402684] R10: 0000000000000014 R11: 0000000000000246 R12: 00007ffa44865441
[    4.402686] R13: 0000556ee8f5bbd0 R14: 0000556ee8f6f0b0 R15: 0000556ee8f688e0
[    4.402690]  </TASK>
[    4.402695] ================================================================================