mwifiex: Add quirk resetting the PCI bridge on MS Surface devices #72

jonas2515 · 2020-11-12T14:24:27Z

The most recent firmware of the 88W8897 card reports a hardcoded LTR
value to the system during initialization, probably as an (unsuccessful)
attempt of the developers to fix firmware crashes. This LTR value
prevents most of the Microsoft Surface devices from entering deep
powersaving states (either platform C-State 10 or S0ix state), because
the exit latency of that state would be higher than what the card can
tolerate.

Turns out the card works just the same (including the firmware crashes)
no matter if that hardcoded LTR value is reported or not, so it's kind
of useless and only prevents us from saving power.

To get rid of those hardcoded LTR reports, it's possible to reset the
PCI bridge device after initializing the cards firmware. I'm not exactly
sure why that works, maybe the power management subsystem of the PCH
resets its stored LTR values when doing a function level reset of the
bridge device. Doing the reset once after starting the wifi firmware
works very well, probably because the firmware only reports that LTR
value a single time during firmware startup.

drivers/net/wireless/marvell/mwifiex/pcie_quirks.h

kitakar5525 · 2020-11-12T17:20:02Z

Thanks to your work on fixing fw crashes, hopefully this bridge reset won't cause fw crashes anymore on all the devices.

So, what about applying this quirk to all the Surface devices? (No effect on Surface 3 and I guess SP3 is the same as well, though. So, you can skip applying for S3 and SP3 for now I think.)

Also, if you intend to revert suspend method back to Host Sleep, this quirk is required for S0ix on suspend.

jonas2515 · 2020-11-17T19:31:21Z

So, what about applying this quirk to all the Surface devices? (No effect on Surface 3 and I guess SP3 is the same as well, though. So, you can skip applying for S3 and SP3 for now I think.)

Also, if you intend to revert suspend method back to Host Sleep, this quirk is required for S0ix on suspend.

Sounds good, indeed I didn't think of the consequences for other devices when re-enabling Host Sleep on all devices.

The most recent firmware of the 88W8897 card reports a hardcoded LTR value to the system during initialization, probably as an (unsuccessful) attempt of the developers to fix firmware crashes. This LTR value prevents most of the Microsoft Surface devices from entering deep powersaving states (either platform C-State 10 or S0ix state), because the exit latency of that state would be higher than what the card can tolerate. Turns out the card works just the same (including the firmware crashes) no matter if that hardcoded LTR value is reported or not, so it's kind of useless and only prevents us from saving power. To get rid of those hardcoded LTR reports, it's possible to reset the PCI bridge device after initializing the cards firmware. I'm not exactly sure why that works, maybe the power management subsystem of the PCH resets its stored LTR values when doing a function level reset of the bridge device. Doing the reset once after starting the wifi firmware works very well, probably because the firmware only reports that LTR value a single time during firmware startup.

jonas2515 · 2021-03-26T13:57:13Z

This targets branch v5.11-surface-devel now.

I've also updated this to add the quirk to all Surface devices except Surface 3 and Pro 3, as suggested by @kitakar5525.

qzed

Thanks, looks good!

The test case btrfs/238 reports the warning below: WARNING: CPU: 3 PID: 481 at fs/btrfs/super.c:2509 btrfs_show_devname+0x104/0x1e8 [btrfs] CPU: 2 PID: 1 Comm: systemd Tainted: G W O 5.14.0-rc1-custom linux-surface#72 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: btrfs_show_devname+0x108/0x1b4 [btrfs] show_mountinfo+0x234/0x2c4 m_show+0x28/0x34 seq_read_iter+0x12c/0x3c4 vfs_read+0x29c/0x2c8 ksys_read+0x80/0xec __arm64_sys_read+0x28/0x34 invoke_syscall+0x50/0xf8 do_el0_svc+0x88/0x138 el0_svc+0x2c/0x8c el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x198/0x19c Reason: While btrfs_prepare_sprout() moves the fs_devices::devices into fs_devices::seed_list, the btrfs_show_devname() searches for the devices and found none, leading to the warning as in above. Fix: latest_dev is updated according to the changes to the device list. That means we could use the latest_dev->name to show the device name in /proc/self/mounts, the pointer will be always valid as it's assigned before the device is deleted from the list in remove or replace. The RCU protection is sufficient as the device structure is freed after synchronization. Reported-by: Su Yue <l@damenly.su> Tested-by: Su Yue <l@damenly.su> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>

Commit 6605fd2 upstream. The test case btrfs/238 reports the warning below: WARNING: CPU: 3 PID: 481 at fs/btrfs/super.c:2509 btrfs_show_devname+0x104/0x1e8 [btrfs] CPU: 2 PID: 1 Comm: systemd Tainted: G W O 5.14.0-rc1-custom #72 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: btrfs_show_devname+0x108/0x1b4 [btrfs] show_mountinfo+0x234/0x2c4 m_show+0x28/0x34 seq_read_iter+0x12c/0x3c4 vfs_read+0x29c/0x2c8 ksys_read+0x80/0xec __arm64_sys_read+0x28/0x34 invoke_syscall+0x50/0xf8 do_el0_svc+0x88/0x138 el0_svc+0x2c/0x8c el0t_64_sync_handler+0x84/0xe4 el0t_64_sync+0x198/0x19c Reason: While btrfs_prepare_sprout() moves the fs_devices::devices into fs_devices::seed_list, the btrfs_show_devname() searches for the devices and found none, leading to the warning as in above. Fix: latest_dev is updated according to the changes to the device list. That means we could use the latest_dev->name to show the device name in /proc/self/mounts, the pointer will be always valid as it's assigned before the device is deleted from the list in remove or replace. The RCU protection is sufficient as the device structure is freed after synchronization. Reported-by: Su Yue <l@damenly.su> Tested-by: Su Yue <l@damenly.su> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 3004081 ] In case runtime PM is enabled, do runtime PM clean up to remove cpu latency qos request, otherwise driver removal may have below kernel dump: [ 19.463299] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000048 [ 19.472161] Mem abort info: [ 19.474985] ESR = 0x0000000096000004 [ 19.478754] EC = 0x25: DABT (current EL), IL = 32 bits [ 19.484081] SET = 0, FnV = 0 [ 19.487149] EA = 0, S1PTW = 0 [ 19.490361] FSC = 0x04: level 0 translation fault [ 19.495256] Data abort info: [ 19.498149] ISV = 0, ISS = 0x00000004 [ 19.501997] CM = 0, WnR = 0 [ 19.504977] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000049f81000 [ 19.511432] [0000000000000048] pgd=0000000000000000, p4d=0000000000000000 [ 19.518245] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 19.524520] Modules linked in: gpio_ir_recv(+) rc_core [last unloaded: rc_core] [ 19.531845] CPU: 0 PID: 445 Comm: insmod Not tainted 6.2.0-rc1-00028-g2c397a46d47c #72 [ 19.531854] Hardware name: FSL i.MX8MM EVK board (DT) [ 19.531859] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 19.551777] pc : cpu_latency_qos_remove_request+0x20/0x110 [ 19.557277] lr : gpio_ir_recv_runtime_suspend+0x18/0x30 [gpio_ir_recv] [ 19.557294] sp : ffff800008ce3740 [ 19.557297] x29: ffff800008ce3740 x28: 0000000000000000 x27: ffff800008ce3d50 [ 19.574270] x26: ffffc7e3e9cea100 x25: 00000000000f4240 x24: ffffc7e3f9ef0e30 [ 19.574284] x23: 0000000000000000 x22: ffff0061803820f4 x21: 0000000000000008 [ 19.574296] x20: ffffc7e3fa75df30 x19: 0000000000000020 x18: ffffffffffffffff [ 19.588570] x17: 0000000000000000 x16: ffffc7e3f9efab70 x15: ffffffffffffffff [ 19.595712] x14: ffff800008ce37b8 x13: ffff800008ce37aa x12: 0000000000000001 [ 19.602853] x11: 0000000000000001 x10: ffffcbe3ec0dff87 x9 : 0000000000000008 [ 19.609991] x8 : 0101010101010101 x7 : 0000000000000000 x6 : 000000000f0bfe9f [ 19.624261] x5 : 00ffffffffffffff x4 : 0025ab8e00000000 x3 : ffff006180382010 [ 19.631405] x2 : ffffc7e3e9ce8030 x1 : ffffc7e3fc3eb810 x0 : 0000000000000020 [ 19.638548] Call trace: [ 19.640995] cpu_latency_qos_remove_request+0x20/0x110 [ 19.646142] gpio_ir_recv_runtime_suspend+0x18/0x30 [gpio_ir_recv] [ 19.652339] pm_generic_runtime_suspend+0x2c/0x44 [ 19.657055] __rpm_callback+0x48/0x1dc [ 19.660807] rpm_callback+0x6c/0x80 [ 19.664301] rpm_suspend+0x10c/0x640 [ 19.667880] rpm_idle+0x250/0x2d0 [ 19.671198] update_autosuspend+0x38/0xe0 [ 19.675213] pm_runtime_set_autosuspend_delay+0x40/0x60 [ 19.680442] gpio_ir_recv_probe+0x1b4/0x21c [gpio_ir_recv] [ 19.685941] platform_probe+0x68/0xc0 [ 19.689610] really_probe+0xc0/0x3dc [ 19.693189] __driver_probe_device+0x7c/0x190 [ 19.697550] driver_probe_device+0x3c/0x110 [ 19.701739] __driver_attach+0xf4/0x200 [ 19.705578] bus_for_each_dev+0x70/0xd0 [ 19.709417] driver_attach+0x24/0x30 [ 19.712998] bus_add_driver+0x17c/0x240 [ 19.716834] driver_register+0x78/0x130 [ 19.720676] __platform_driver_register+0x28/0x34 [ 19.725386] gpio_ir_recv_driver_init+0x20/0x1000 [gpio_ir_recv] [ 19.731404] do_one_initcall+0x44/0x2ac [ 19.735243] do_init_module+0x48/0x1d0 [ 19.739003] load_module+0x19fc/0x2034 [ 19.742759] __do_sys_finit_module+0xac/0x12c [ 19.747124] __arm64_sys_finit_module+0x20/0x30 [ 19.751664] invoke_syscall+0x48/0x114 [ 19.755420] el0_svc_common.constprop.0+0xcc/0xec [ 19.760132] do_el0_svc+0x38/0xb0 [ 19.763456] el0_svc+0x2c/0x84 [ 19.766516] el0t_64_sync_handler+0xf4/0x120 [ 19.770789] el0t_64_sync+0x190/0x194 [ 19.774460] Code: 910003fd a90153f3 aa0003f3 91204021 (f9401400) [ 19.780556] ---[ end trace 0000000000000000 ]--- Signed-off-by: Li Jun <jun.li@nxp.com> Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

jonas2515 mentioned this pull request Nov 12, 2020

Properly fix wifi firmware crashes #70

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qzed requested changes Nov 12, 2020

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drivers/net/wireless/marvell/mwifiex/pcie_quirks.h Outdated Show resolved Hide resolved

jonas2515 force-pushed the v5.9-surface-devel-reset-parent-bridge branch from b5fbb78 to bb36502 Compare March 26, 2021 13:55

jonas2515 changed the base branch from v5.9-surface-devel to v5.11-surface-devel March 26, 2021 13:56

jonas2515 changed the title ~~mwifiex: Add quirk resetting the PCI bridge on Surface Pro 5 devices~~ mwifiex: Add quirk resetting the PCI bridge on MS Surface devices Mar 26, 2021

qzed approved these changes Mar 26, 2021

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qzed merged commit dd9a004 into linux-surface:v5.11-surface-devel Mar 26, 2021

qzed mentioned this pull request Mar 29, 2021

Announcements and updates linux-surface/linux-surface#96

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nexplorer-3e mentioned this pull request May 18, 2024

Mwifiex: tx timeout randomly occurs in AP mode #155

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mwifiex: Add quirk resetting the PCI bridge on MS Surface devices #72

mwifiex: Add quirk resetting the PCI bridge on MS Surface devices #72

jonas2515 commented Nov 12, 2020 •

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mwifiex: Add quirk resetting the PCI bridge on MS Surface devices #72

mwifiex: Add quirk resetting the PCI bridge on MS Surface devices #72

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