Re: smsc911x_suspend crash (was: Re: [PATCH] ARM: shmobile: r8a7778: Add missing call to shmobile_in

[Florian Fainelli <f.fainelli@gmail.com>]

Hi Geert,

On 08/14/2014 01:52 AM, Geert Uytterhoeven wrote:
> Hi Simon,
> 
> (taking this to netdev for the crash in smsc911x_suspend())
> 
> On Thu, Aug 14, 2014 at 8:16 AM, Simon Horman <horms@verge.net.au> wrote:
>> while this may be part of the puzzle my light testing shows
>> that suspend-to-ram does not appear to work with this patch applied.
> 
> Thanks for testing!

Sounds like you are another victim of:
a71e3c37960ce5f9 ("net: phy: Set the driver when registering an MDIO bus
device")

which got reverted just recently:
ce7991e8198b80eb6b4441b6f6114bea4a665d66 ("Revert "net: phy: Set the
driver when registering an MDIO bus device"").

> 
>> My procedure is as followw.
>>
>> 1. Apply this patch on top of renesas-devel-v3.16-20140811
>> 2. make bockw_defconfig
>> 3. Select CONFIG_SUSPEND
>> 4. Update r8a7778-bockw.dts to include no_console_suspend in bootargs
> 
> Alternative:
> 
> echo 0 > /sys/module/printk/parameters/console_suspend
> 
>> 4. Boot and then:
>>
>>    i. echo enabled > /sys/devices/platform/sh-sci.0/tty/ttySC0/power/wakeup
>>    ii. echo mem > /sys/power/wakeup_count
> 
> Uh?
> 
> echo mem > /sys/power/state
> 
>> root@debian:~# echo mem > /sys/power/wakeup_count
>> -bash: echo: write error: Invalid argument
> 
> I guess there's an "echo mem > /sys/power/state" here?
> 
>> INIT: Id "2" respawning too fast: disabled for 5 minutes
>> INIT: Id "1" respawning too fast: disabled for 5 minutes
>> ate
>> PM: Syncing filesystems ... done.
>> Freezing user space processes ... (elapsed 0.002 seconds) done.
>> Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
>> rtc-rx8581 0-0051: low voltage detected, date/time is not reliable.
>> Unable to handle kernel NULL pointer dereference at virtual address 00000620
>> pgd = cfbec000
>> [00000620] *pgdobd1831, *pte\0000000, *ppte\0000000
>> Internal error: Oops: 17 [#1] ARM
>> CPU: 0 PID: 1591 Comm: bash Not tainted 3.16.0-00001-g535da58-dirty #44
>> task: cfaa54c0 ti: cfaa8000 task.ti: cfaa8000
>> PC is at smsc911x_suspend+0x18/0x3c
>> LR is at dpm_run_callback.isra.11+0x24/0x50
>> pc : [<c01d588c>]    lr : [<c019c004>]    psr: a0000093
>> sp : cfaa9d98  ip : cfaa9db0  fp : cfaa9dac
>> r10: 00000000  r9 : c03fbe78  r8 : 00000000
>> r7 : cfa24474  r6 : c0426b7c  r5 : c01d5874  r4 : a0000013
>> r3 : 00000000  r2 : 00000000  r1 : cfa24440  r0 : 00000000
> 
> drivers/net/ethernet/smsc/smsc911x.c:
> 
> static int smsc911x_suspend(struct device *dev)
> {
>         struct net_device *ndev = dev_get_drvdata(dev);
> 
> So ndev = NULL, boom!
> 
>         struct smsc911x_data *pdata = netdev_priv(ndev);
> 
>         /* enable wake on LAN, energy detection and the external PME
>          * signal. */
>         smsc911x_reg_write(pdata, PMT_CTRL,
>                 PMT_CTRL_PM_MODE_D1_ | PMT_CTRL_WOL_EN_ |
>                 PMT_CTRL_ED_EN_ | PMT_CTRL_PME_EN_);
> 
>         return 0;
> }
> 
> However, I don't immediately see how this can be NULL.
> smsc911x_drv_probe() does call "platform_set_drvdata(pdev, dev);".
> 
> And
> 
>         struct net_device *ndev = dev_get_drvdata(dev);
> 
> should be equivalent to
> 
>         struct platform_device *pdev = to_platform_device(dev);
>         struct net_device *ndev = platform_get_drvdata(pdev);
> 
> Another SMSC driver, drivers/net/ethernet/smsc/smc91x.c has an explicit
> NULL-check for ndev:
> 
> static int smc_drv_resume(struct device *dev)
> {
>         struct platform_device *pdev = to_platform_device(dev);
>         struct net_device *ndev = platform_get_drvdata(pdev);
> 
>         if (ndev) {
>                 struct smc_local *lp = netdev_priv(ndev);
>                 ....
>         }
>         return 0;
> }
> 
> But other drivers like igb don't.
> 
> Anyone with a clue? Thanks!
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
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