[BUG] iwlwifi: card unusable after firmware crash

[BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, everyone,

I'm running Linux 5.10-rc7 with this firmware/hardware:

[    1.431878] iwlwifi 0000:02:00.0: loaded firmware version
29.198743027.0 7265D-29.ucode op_mode iwlmvm
[    1.431899] iwlwifi 0000:02:00.0: Detected Intel(R) Dual Band
Wireless AC 3165, REV=0x210

Most of the time, after disabling/enabling Wi-Fi (or, say, rebooting
the router), the card dies and only comes back after reboot. This is
the relevant dmesg output:

[ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
[ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)
[ 3174.040788] iwlwifi 0000:02:00.0: iwlwifi transaction failed,
dumping registers
[ 3174.040790] iwlwifi 0000:02:00.0: iwlwifi device config registers:
[ 3174.041008] iwlwifi 0000:02:00.0: 00000000: 31668086 00100406
02800099 00000010 c1100004 00000000 00000000 00000000
[ 3174.041010] iwlwifi 0000:02:00.0: 00000020: 00000000 00000000
00000000 42108086 00000000 000000c8 00000000 000001ff
[ 3174.041011] iwlwifi 0000:02:00.0: 00000040: 00020010 10008ec0
00100c10 0046e811 10110142 00000000 00000000 00000000
[ 3174.041013] iwlwifi 0000:02:00.0: 00000060: 00000000 00080812
00000005 00000000 00010001 00000000 00000000 00000000
[ 3174.041014] iwlwifi 0000:02:00.0: 00000080: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041016] iwlwifi 0000:02:00.0: 000000a0: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041017] iwlwifi 0000:02:00.0: 000000c0: 00000000 00000000
c823d001 0d000000 00814005 fee00318 00000000 00000000
[ 3174.041019] iwlwifi 0000:02:00.0: 000000e0: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041020] iwlwifi 0000:02:00.0: 00000100: 14010001 00000000
00000000 00462031 00000000 00002000 00000000 00000000
[ 3174.041022] iwlwifi 0000:02:00.0: 00000120: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041023] iwlwifi 0000:02:00.0: 00000140: 14c10003 ff75a50d
e09467ff 15410018 10031003 0001001e 00f01e1f 6003000b
[ 3174.041024] iwlwifi 0000:02:00.0: iwlwifi device memory mapped registers:
[ 3174.041075] iwlwifi 0000:02:00.0: 00000000: 00800000 00000000
00000080 00000000 00000000 00000000 00000000 00000000
[ 3174.041076] iwlwifi 0000:02:00.0: 00000020: 00000001 080003d8
00000210 d55555d5 00000000 d55555d5 80008040 00080042
[ 3174.041088] iwlwifi 0000:02:00.0: iwlwifi device AER capability structure:
[ 3174.041112] iwlwifi 0000:02:00.0: 00000000: 14010001 00000000
00000000 00462031 00000000 00002000 00000000 00000000
[ 3174.041113] iwlwifi 0000:02:00.0: 00000020: 00000000 00000000 00000000
[ 3174.041114] iwlwifi 0000:02:00.0: iwlwifi parent port
(0000:00:1c.5) config registers:
[ 3174.041198] iwlwifi 0000:00:1c.5: 00000000: 9d158086 00100407
060400f1 00810010 00000000 00000000 00020200 200000f0
[ 3174.041200] iwlwifi 0000:00:1c.5: 00000020: c110c110 0001fff1
00000000 00000000 00000000 00000040 00000000 000202ff
[ 3174.041201] iwlwifi 0000:00:1c.5: 00000040: 01428010 00008001
00110000 06724813 70110042 002cb200 01400000 00000000
[ 3174.041203] iwlwifi 0000:00:1c.5: 00000060: 00000000 00000037
00000000 0000000e 00010003 00000000 00000000 00000000
[ 3174.041204] iwlwifi 0000:00:1c.5: 00000080: 00019005 fee00258
00000000 00000000 0000a00d 382a17aa 00000000 00000000
[ 3174.041206] iwlwifi 0000:00:1c.5: 000000a0: c8030001 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041207] iwlwifi 0000:00:1c.5: 000000c0: 00000000 00000000
00000000 00000000 07001001 00001842 8b1e0008 00000000
[ 3174.041209] iwlwifi 0000:00:1c.5: 000000e0: 00630300 00000000
00100006 00000000 00000050 4c000000 08230fb3 02000004
[ 3174.041210] iwlwifi 0000:00:1c.5: 00000100: 14000000 00000000
00000000 00060011 00000001 00002000 00000000 00000000
[ 3174.041211] iwlwifi 0000:00:1c.5: 00000120: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041213] iwlwifi 0000:00:1c.5: 00000140: 2001000d 0000000f
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041214] iwlwifi 0000:00:1c.5: 00000160: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041216] iwlwifi 0000:00:1c.5: 00000180: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041217] iwlwifi 0000:00:1c.5: 000001a0: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041218] iwlwifi 0000:00:1c.5: 000001c0: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041220] iwlwifi 0000:00:1c.5: 000001e0: 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
[ 3174.041221] iwlwifi 0000:00:1c.5: 00000200: 2201001e 0028281f 6003280b

I also had this problem with the previous firmware version. Any ideas
about what could be causing it?

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Jakub Kicinski]

On Tue, 8 Dec 2020 11:27:50 +0000 Rui Salvaterra wrote:
> Hi, everyone,
> 
> I'm running Linux 5.10-rc7 with this firmware/hardware:
> 
> [    1.431878] iwlwifi 0000:02:00.0: loaded firmware version
> 29.198743027.0 7265D-29.ucode op_mode iwlmvm
> [    1.431899] iwlwifi 0000:02:00.0: Detected Intel(R) Dual Band
> Wireless AC 3165, REV=0x210
> 
> Most of the time, after disabling/enabling Wi-Fi (or, say, rebooting
> the router), the card dies and only comes back after reboot. This is
> the relevant dmesg output:

Just to confirm - is this a regression in 5.10-rc? Does 5.9 work
smoothly in the problematic scenario?

Re: [BUG] iwlwifi: card unusable after firmware crash

[Coelho, Luciano]

On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:
> Hi, everyone,
> 
> I'm running Linux 5.10-rc7 with this firmware/hardware:
> 
> [    1.431878] iwlwifi 0000:02:00.0: loaded firmware version
> 29.198743027.0 7265D-29.ucode op_mode iwlmvm
> [    1.431899] iwlwifi 0000:02:00.0: Detected Intel(R) Dual Band
> Wireless AC 3165, REV=0x210
> 
> Most of the time, after disabling/enabling Wi-Fi (or, say, rebooting
> the router), the card dies and only comes back after reboot. This is
> the relevant dmesg output:
> 
> [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)

It looks like your machine is reporting RF-Kill to the WiFi device.

There seems to be some sort of race there that is causing us to still
try to communicate with the device (and thus you see the transaction
failed dump), but that will obviously fail when RF-Kill is enabled.

--
Luca.

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, Jakub,

On Tue, 8 Dec 2020 at 16:06, Jakub Kicinski <kuba@kernel.org> wrote:
>
> Just to confirm - is this a regression in 5.10-rc? Does 5.9 work
> smoothly in the problematic scenario?

Good question. It's definitely a regression, though I don't remember
exactly the last working version I had. I *think* 5.9 was working, but
I can't be sure without testing.

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, Luca,

On Tue, 8 Dec 2020 at 16:27, Coelho, Luciano <luciano.coelho@intel.com> wrote:
>
> On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:
> >
> > [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> > [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)
>
> It looks like your machine is reporting RF-Kill to the WiFi device.

Yes, that's an artifact of how I tested: I rebooted the router, the
Wi-Fi interface disassociated and the dmesg was clean. However, after
the router came up, the laptop didn't reconnect (and the connection
had completely disappeared from nmtui). Afterwards, I did the rfkill
cycle you see, and only then I got the register dump.

> There seems to be some sort of race there that is causing us to still
> try to communicate with the device (and thus you see the transaction
> failed dump), but that will obviously fail when RF-Kill is enabled.

I'm not sure about that, the card was already dead before the rfkill cycle.

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Jakub Kicinski]

On Tue, 8 Dec 2020 23:17:48 +0000 Rui Salvaterra wrote:
> Hi, Luca,
> 
> On Tue, 8 Dec 2020 at 16:27, Coelho, Luciano <luciano.coelho@intel.com> wrote:
> > On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:  
> > >
> > > [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> > > [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)  
> >
> > It looks like your machine is reporting RF-Kill to the WiFi device.  
> 
> Yes, that's an artifact of how I tested: I rebooted the router, the
> Wi-Fi interface disassociated and the dmesg was clean. However, after
> the router came up, the laptop didn't reconnect (and the connection
> had completely disappeared from nmtui). Afterwards, I did the rfkill
> cycle you see, and only then I got the register dump.
> 
> > There seems to be some sort of race there that is causing us to still
> > try to communicate with the device (and thus you see the transaction
> > failed dump), but that will obviously fail when RF-Kill is enabled.  
> 
> I'm not sure about that, the card was already dead before the rfkill cycle.

Any luck figuring this out, Luca? If this is a 5.10 regression we need
to let Linus know tomorrow, so the time is ticking :(

Re: [BUG] iwlwifi: card unusable after firmware crash

[Coelho, Luciano]

Hi Jakub et al,

On Wed, 2020-12-09 at 09:13 -0800, Jakub Kicinski wrote:
> On Tue, 8 Dec 2020 23:17:48 +0000 Rui Salvaterra wrote:
> > Hi, Luca,
> > 
> > On Tue, 8 Dec 2020 at 16:27, Coelho, Luciano <luciano.coelho@intel.com> wrote:
> > > On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:  
> > > > 
> > > > [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> > > > [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)  
> > > 
> > > It looks like your machine is reporting RF-Kill to the WiFi device.  
> > 
> > Yes, that's an artifact of how I tested: I rebooted the router, the
> > Wi-Fi interface disassociated and the dmesg was clean. However, after
> > the router came up, the laptop didn't reconnect (and the connection
> > had completely disappeared from nmtui). Afterwards, I did the rfkill
> > cycle you see, and only then I got the register dump.
> > 
> > > There seems to be some sort of race there that is causing us to still
> > > try to communicate with the device (and thus you see the transaction
> > > failed dump), but that will obviously fail when RF-Kill is enabled.  
> > 
> > I'm not sure about that, the card was already dead before the rfkill cycle.
> 
> Any luck figuring this out, Luca? If this is a 5.10 regression we need
> to let Linus know tomorrow, so the time is ticking :(

I just checked all the commits in iwlwifi between v5.9 and v5.10 and I
don't see anything that could affect how RF-Kill works.

Emmanuel, do you remember anything that went in that could have
affected RF-Kill?

--
Cheers,
Luca.

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, guys,

On Wed, 9 Dec 2020 at 17:13, Jakub Kicinski <kuba@kernel.org> wrote:
>
> Any luck figuring this out, Luca? If this is a 5.10 regression we need
> to let Linus know tomorrow, so the time is ticking :(

I don't have the possibility to test other kernels at the moment, but
I will do so in a few days (at least to find a working version to
bisect). Meanwhile, I don't know if this is relevant or not, but I'm
using WPA3 PSK.

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Emmanuel Grumbach]

On Wed, Dec 9, 2020 at 7:19 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Tue, 8 Dec 2020 23:17:48 +0000 Rui Salvaterra wrote:
> > Hi, Luca,
> >
> > On Tue, 8 Dec 2020 at 16:27, Coelho, Luciano <luciano.coelho@intel.com> wrote:
> > > On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:
> > > >
> > > > [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> > > > [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)
> > >
> > > It looks like your machine is reporting RF-Kill to the WiFi device.
> >
> > Yes, that's an artifact of how I tested: I rebooted the router, the
> > Wi-Fi interface disassociated and the dmesg was clean. However, after
> > the router came up, the laptop didn't reconnect (and the connection
> > had completely disappeared from nmtui). Afterwards, I did the rfkill
> > cycle you see, and only then I got the register dump.
> >
> > > There seems to be some sort of race there that is causing us to still
> > > try to communicate with the device (and thus you see the transaction
> > > failed dump), but that will obviously fail when RF-Kill is enabled.
> >
> > I'm not sure about that, the card was already dead before the rfkill cycle.
>
> Any luck figuring this out, Luca? If this is a 5.10 regression we need
> to let Linus know tomorrow, so the time is ticking :(

Rui, I looked at the register dump and looks like you're using AMT on
your system?
Can you confirm?

Re: [BUG] iwlwifi: card unusable after firmware crash

[Emmanuel Grumbach]

On Wed, Dec 9, 2020 at 10:32 PM Emmanuel Grumbach <egrumbach@gmail.com> wrote:
>
> On Wed, Dec 9, 2020 at 7:19 PM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Tue, 8 Dec 2020 23:17:48 +0000 Rui Salvaterra wrote:
> > > Hi, Luca,
> > >
> > > On Tue, 8 Dec 2020 at 16:27, Coelho, Luciano <luciano.coelho@intel.com> wrote:
> > > > On Tue, 2020-12-08 at 11:27 +0000, Rui Salvaterra wrote:
> > > > >
> > > > > [ 3174.003910] iwlwifi 0000:02:00.0: RF_KILL bit toggled to disable radio.
> > > > > [ 3174.003913] iwlwifi 0000:02:00.0: reporting RF_KILL (radio disabled)
> > > >
> > > > It looks like your machine is reporting RF-Kill to the WiFi device.
> > >
> > > Yes, that's an artifact of how I tested: I rebooted the router, the
> > > Wi-Fi interface disassociated and the dmesg was clean. However, after
> > > the router came up, the laptop didn't reconnect (and the connection
> > > had completely disappeared from nmtui). Afterwards, I did the rfkill
> > > cycle you see, and only then I got the register dump.
> > >
> > > > There seems to be some sort of race there that is causing us to still
> > > > try to communicate with the device (and thus you see the transaction
> > > > failed dump), but that will obviously fail when RF-Kill is enabled.
> > >
> > > I'm not sure about that, the card was already dead before the rfkill cycle.
> >
> > Any luck figuring this out, Luca? If this is a 5.10 regression we need
> > to let Linus know tomorrow, so the time is ticking :(
>
> Rui, I looked at the register dump and looks like you're using AMT on
> your system?
> Can you confirm?

Besides, don't you get a stack dump in the vicinity of this register
dump? That's be helpful to see.

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, Emmanuel,

On Wed, 9 Dec 2020 at 20:32, Emmanuel Grumbach <egrumbach@gmail.com> wrote:
>
> Rui, I looked at the register dump and looks like you're using AMT on
> your system?
> Can you confirm?

AMT? You mean Intel Active Management? Heavens, no, not that I know
of! This is a personal laptop (Lenovo B51-80). (And I'd personally
kill the ME with fire, if I could.)

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, again,

On Wed, 9 Dec 2020 at 20:40, Emmanuel Grumbach <egrumbach@gmail.com> wrote:
>
> Besides, don't you get a stack dump in the vicinity of this register
> dump? That's be helpful to see.

Nope. No stack trace at all. Only the register dump.

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Emmanuel Grumbach]

On Wed, Dec 9, 2020 at 10:40 PM Rui Salvaterra <rsalvaterra@gmail.com> wrote:
>
> Hi, Emmanuel,
>
> On Wed, 9 Dec 2020 at 20:32, Emmanuel Grumbach <egrumbach@gmail.com> wrote:
> >
> > Rui, I looked at the register dump and looks like you're using AMT on
> > your system?
> > Can you confirm?
>
> AMT? You mean Intel Active Management? Heavens, no, not that I know
> of! This is a personal laptop (Lenovo B51-80). (And I'd personally
> kill the ME with fire, if I could.)

Yes, I mean that thing. No VPRO sticker on the laptop?
Weird... So apparently I was wrong about the register value.

>
> Thanks,
> Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Emmanuel Grumbach]

On Wed, Dec 9, 2020 at 10:47 PM Emmanuel Grumbach <egrumbach@gmail.com> wrote:
>
> On Wed, Dec 9, 2020 at 10:40 PM Rui Salvaterra <rsalvaterra@gmail.com> wrote:
> >
> > Hi, Emmanuel,
> >
> > On Wed, 9 Dec 2020 at 20:32, Emmanuel Grumbach <egrumbach@gmail.com> wrote:
> > >
> > > Rui, I looked at the register dump and looks like you're using AMT on
> > > your system?
> > > Can you confirm?
> >
> > AMT? You mean Intel Active Management? Heavens, no, not that I know
> > of! This is a personal laptop (Lenovo B51-80). (And I'd personally
> > kill the ME with fire, if I could.)
>
> Yes, I mean that thing. No VPRO sticker on the laptop?
> Weird... So apparently I was wrong about the register value.

Indeed, the bit is reverse logic. So we can put that aside.
Frankly, I have no clue. You can try our backport tree to bisect,
should be easier..
What I see here is that your GP_CTRL value is 080003d8

#define CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW          (0x08000000)
which means sense since apparently, HW RF-Kill was asserted.
#define CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP         (0x00000010)
Which means that the device is going to sleep... And that's the problem:

iwl_trans_pcie_grab_nic_access:
        ret = iwl_poll_bit(trans, CSR_GP_CNTRL,
                           CSR_GP_CNTRL_REG_VAL_MAC_ACCESS_EN,
                           (CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY |
                            CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP), 15000);
        if (unlikely(ret < 0)) {
                u32 cntrl = iwl_read32(trans, CSR_GP_CNTRL);

                WARN_ONCE(1,
                          "Timeout waiting for hardware access
(CSR_GP_CNTRL 0x%08x)\n",
                          cntrl);

but I'd expect the splat in your log...
Or maybe you can't load the firmware?

Can you try this:
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 2fffbbc8462f..748300752630 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2121,6 +2121,7 @@ static bool
iwl_trans_pcie_grab_nic_access(struct iwl_trans *trans,
         * track nic_access anyway.
         */
        __release(&trans_pcie->reg_lock);
+       mdelay(1);
        return true;
 }

If that helps, then... I'd have no clue why it helps, but this
specific device caused us trouble like bad timing after
grab_nic_access..


>
> >
> > Thanks,
> > Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi again, Emmanuel,

On Wed, 9 Dec 2020 at 21:07, Emmanuel Grumbach <egrumbach@gmail.com> wrote:
>
> Indeed, the bit is reverse logic. So we can put that aside.
> Frankly, I have no clue. You can try our backport tree to bisect,
> should be easier..
> What I see here is that your GP_CTRL value is 080003d8
>
> #define CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW          (0x08000000)
> which means sense since apparently, HW RF-Kill was asserted.
> #define CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP         (0x00000010)
> Which means that the device is going to sleep... And that's the problem:
>
> iwl_trans_pcie_grab_nic_access:
>         ret = iwl_poll_bit(trans, CSR_GP_CNTRL,
>                            CSR_GP_CNTRL_REG_VAL_MAC_ACCESS_EN,
>                            (CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY |
>                             CSR_GP_CNTRL_REG_FLAG_GOING_TO_SLEEP), 15000);
>         if (unlikely(ret < 0)) {
>                 u32 cntrl = iwl_read32(trans, CSR_GP_CNTRL);
>
>                 WARN_ONCE(1,
>                           "Timeout waiting for hardware access
> (CSR_GP_CNTRL 0x%08x)\n",
>                           cntrl);
>
> but I'd expect the splat in your log...
> Or maybe you can't load the firmware?

Well, my kernel doesn't have any modules, it's all built-in. The
firmware is obviously loading fine, otherwise the card wouldn't work,
but yeah, that WARN_ONCE hasn't triggered at all.

> Can you try this:
> diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
> b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
> index 2fffbbc8462f..748300752630 100644
> --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
> +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
> @@ -2121,6 +2121,7 @@ static bool
> iwl_trans_pcie_grab_nic_access(struct iwl_trans *trans,
>          * track nic_access anyway.
>          */
>         __release(&trans_pcie->reg_lock);
> +       mdelay(1);
>         return true;
>  }
>
> If that helps, then... I'd have no clue why it helps, but this
> specific device caused us trouble like bad timing after
> grab_nic_access..

I'll give it a spin. Nasty hack, but if it works, it works. :)

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Rui Salvaterra]

Hi, again,

I haven't tested any patch or bisected, but I have another data point.
I built and tested Linux 5.8.18, with the same firmware, and it is
working correctly. I reduced the test case to just rfkilling the
connection, which showed the register dump immediately (before that I
was using the airplane toggle on the keyboard, which isn't working
correctly, it disables and immediately reenables the radio, for some
unfathomable reason).
So, now I'm inclined to believe this is some sort of race condition
between rfkill and pending transactions.

Thanks,
Rui

Re: [BUG] iwlwifi: card unusable after firmware crash

[Emmanuel Grumbach]

Hi,

> Hi, again,
>
> I haven't tested any patch or bisected, but I have another data point.
> I built and tested Linux 5.8.18, with the same firmware, and it is
> working correctly. I reduced the test case to just rfkilling the
> connection, which showed the register dump immediately (before that I
> was using the airplane toggle on the keyboard, which isn't working
> correctly, it disables and immediately reenables the radio, for some
> unfathomable reason).
> So, now I'm inclined to believe this is some sort of race condition
> between rfkill and pending transactions.

Which also means it's not a regression.
You can add a dump_stack() in the function that dumps the registers to
get a clue.