linux-kernel - Re: [BUG] iwlwifi: card unusable after firmware crash

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Date:   Wed, 9 Dec 2020 23:07:09 +0200
From:   Emmanuel Grumbach <egrumbach@...il.com>
To:     Rui Salvaterra <rsalvaterra@...il.com>
Cc:     Jakub Kicinski <kuba@...nel.org>,
        "Coelho, Luciano" <luciano.coelho@...el.com>,
        "Goodstein, Mordechay" <mordechay.goodstein@...el.com>,
        "Berg, Johannes" <johannes.berg@...el.com>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] iwlwifi: card unusable after firmware crash

On Wed, Dec 9, 2020 at 10:47 PM Emmanuel Grumbach <egrumbach@...il.com> wrote:
>
> On Wed, Dec 9, 2020 at 10:40 PM Rui Salvaterra <rsalvaterra@...il.com> wrote:
> >
> > Hi, Emmanuel,
> >
> > On Wed, 9 Dec 2020 at 20:32, Emmanuel Grumbach <egrumbach@...il.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