Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
> To support 36-bit DMA, configure chip proprietary bit via PCI config API
> or chip DBI interface. However, the PCI device mmap isn't set yet and
> the DBI is also inaccessible via mmap, so only if the bit can be accessible
> via PCI config API, chip can support 36-bit DMA. Otherwise, fallback to
> 32-bit DMA.
>
> With NULL mmap address, kernel throws trace:
>
> BUG: unable to handle page fault for address: 0000000000001090
> #PF: supervisor write access in kernel mode
> #PF: error_code(0x0002) - not-present page
> PGD 0 P4D 0
> Oops: Oops: 0002 [#1] PREEMPT SMP PTI
> CPU: 1 UID: 0 PID: 71 Comm: irq/26-pciehp Tainted: G OE 6.14.2-061402-generic #202504101348
> Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> RIP: 0010:rtw89_pci_ops_write16+0x12/0x30 [rtw89_pci]
> RSP: 0018:ffffb0ffc0acf9d8 EFLAGS: 00010206
> RAX: ffffffffc158f9c0 RBX: ffff94865e702020 RCX: 0000000000000000
> RDX: 0000000000000718 RSI: 0000000000001090 RDI: ffff94865e702020
> RBP: ffffb0ffc0acf9d8 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000015
> R13: 0000000000000719 R14: ffffb0ffc0acfa1f R15: ffffffffc1813060
> FS: 0000000000000000(0000) GS:ffff9486f3480000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000001090 CR3: 0000000090440001 CR4: 00000000000626f0
> Call Trace:
> <TASK>
> rtw89_pci_read_config_byte+0x6d/0x120 [rtw89_pci]
> rtw89_pci_cfg_dac+0x5b/0xb0 [rtw89_pci]
> rtw89_pci_probe+0xa96/0xbd0 [rtw89_pci]
> ? __pfx___device_attach_driver+0x10/0x10
> ? __pfx___device_attach_driver+0x10/0x10
> local_pci_probe+0x47/0xa0
> pci_call_probe+0x5d/0x190
> pci_device_probe+0xa7/0x160
> really_probe+0xf9/0x370
> ? pm_runtime_barrier+0x55/0xa0
> __driver_probe_device+0x8c/0x140
> driver_probe_device+0x24/0xd0
> __device_attach_driver+0xcd/0x170
> bus_for_each_drv+0x99/0x100
> __device_attach+0xb4/0x1d0
> device_attach+0x10/0x20
> pci_bus_add_device+0x59/0x90
> pci_bus_add_devices+0x31/0x80
> pciehp_configure_device+0xaa/0x170
> pciehp_enable_slot+0xd6/0x240
> pciehp_handle_presence_or_link_change+0xf1/0x180
> pciehp_ist+0x162/0x1c0
> irq_thread_fn+0x24/0x70
> irq_thread+0xef/0x1c0
> ? __pfx_irq_thread_fn+0x10/0x10
> ? __pfx_irq_thread_dtor+0x10/0x10
> ? __pfx_irq_thread+0x10/0x10
> kthread+0xfc/0x230
> ? __pfx_kthread+0x10/0x10
> ret_from_fork+0x47/0x70
> ? __pfx_kthread+0x10/0x10
> ret_from_fork_asm+0x1a/0x30
> </TASK>
>
> Fixes: 1fd4b3fe52ef ("wifi: rtw89: pci: support 36-bit PCI DMA address")
> Reported-by: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
> Closes: https://lore.kernel.org/linux-wireless/ccaf49b6-ff41-4917-90f1-f53cadaaa0da@xxxxxxxxx/T/#u
> Closes: https://github.com/openwrt/openwrt/issues/17025
> Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
1 patch(es) applied to rtw-next branch of rtw.git, thanks.
a70cf04b08f4 wifi: rtw89: pci: configure manual DAC mode via PCI config API only
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https://github.com/pkshih/rtw.git
