Re: [PATCH] i2c-omap: Trigger bus recovery in lockup case

[Sebastian Reichel <sebastian.reichel@collabora.co.uk>]

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Hi,

On Fri, Sep 29, 2017 at 05:17:47PM +0200, Claudio Foellmi wrote:
> >> Sebastian, can you please check if this helps with your problems on N950?
> >> If it does, I'll turn it into a proper standalone patch.
> > 
> > No, it does not. Also no interrupts ignoring messages appearing
> > in dmesg:
> > 
> > n950# dmesg | grep -E "48072000.i2c|lp5523x"
> > [    0.791046] omap_i2c 48072000.i2c: bus 1 rev4.4 at 400 kHz
> > [    4.934265] lp5523x 1-0032: reset command sent (no ACK)!
> > [    6.003875] omap_i2c 48072000.i2c: controller timed out
> > [    6.033874] lp5523x 1-0032: device detection err: -110
> > [    6.039154] lp5523x: probe of 1-0032 failed with error -110
> > 
> 
> Hi Sebastian
> 
> Thank you for trying it out.
> It seems that your symptoms are quite different from the ones that Vignesh
> described earlier. He had never-ending storms of spurious interrupts
> (which that patch would have addressed), but you don't seem to get
> any interrupts at all. Not even the NACK one, which just looks wrong.
> 
> If you want to still dig deeper, you can enable debug logs for i2c-omap,
> so you can see every single interrupt. But if there are none, I don't see
> what we could possibly do to fix it.
> 
> 
> Vignesh, do you still have access to any of those devices with interrupt
> floods? If so, could you try the previous patch on one of them?
> 
> Also note that Sebastian's issue is definitely not caused (or helped)
> by bus recovery, the timeout he sees resets the adapter right away.
> So he is not affected by my original patch either way.
> 
> -- Claudio

Yeah, I don't see IRQ storm, so this might be a different issue.
FWIW this is what I see on N950:

n950# dmesg | grep -E "48072000.i2c|lp55"
[    2.136383] omap_i2c 48072000.i2c: bus 1 rev4.4 at 400 kHz
[    8.212951] omap_i2c 48072000.i2c: addr: 0x0032, len: 2, flags: 0x0, stop: 1
[    8.213287] omap_i2c 48072000.i2c: IRQ (ISR = 0x0010)
[    8.213592] omap_i2c 48072000.i2c: IRQ (ISR = 0x0002)
[    8.213897] lp5523x 1-0032: reset command sent (no ACK)!
[    8.242462] omap_i2c 48072000.i2c: addr: 0x0032, len: 2, flags: 0x0, stop: 1
[    8.243255] omap_i2c 48072000.i2c: IRQ (ISR = 0x0014)
[    8.243469] omap_i2c 48072000.i2c: IRQ (ISR = 0x0010)
[    8.253387] omap_i2c 48072000.i2c: addr: 0x0032, len: 1, flags: 0x0, stop: 0
[    8.253631] omap_i2c 48072000.i2c: IRQ (ISR = 0x0010)
[    9.272735] omap_i2c 48072000.i2c: controller timed out
[    9.278167] lp5523x 1-0032: device detection err: -110
[    9.283843] lp5523x: probe of 1-0032 failed with error -110
[    9.662780] omap_i2c 48072000.i2c: addr: 0x0060, len: 1, flags: 0x0, stop: 0
[    9.670166] omap_i2c 48072000.i2c: IRQ (ISR = 0x0010)
[    9.675659] omap_i2c 48072000.i2c: IRQ (ISR = 0x0004)
[    9.682617] omap_i2c 48072000.i2c: addr: 0x0060, len: 1, flags: 0x1, stop: 1
[    9.689819] omap_i2c 48072000.i2c: IRQ (ISR = 0x0008)
[    9.695007] omap_i2c 48072000.i2c: IRQ (ISR = 0x0004)

-- Sebastian

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