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From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Andreas Kemnade <andreas@kemnade.info>, Tony Lindgren <tony@atomide.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-omap <linux-omap@vger.kernel.org>,
	Adam Ford <aford173@gmail.com>, "Andrew F . Davis" <afd@ti.com>,
	Vignesh R <vigneshr@ti.com>
Subject: Re: [PATCHv3] w1: omap-hdq: Simplify driver with PM runtime autosuspend
Date: Sat, 25 Apr 2020 12:37:01 +0200	[thread overview]
Message-ID: <E8575FE4-4BC2-41B7-B574-339C58D9CB5E@goldelico.com> (raw)
In-Reply-To: <44AD9673-AE02-498F-A5CC-48499DF226E3@goldelico.com>


> Am 25.04.2020 um 12:29 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
> 
> H
> The things start to get "fixed" when the hdq_isr
> jumps to 6 indicating
> 
> OMAP_HDQ_INT_STATUS_RXCOMPLETE | OMAP_HDQ_INT_STATUS_TXCOMPLETE
> 
> So I am getting more inclined to believe that it is
> not a power management issue but some piggybacked
> change to how interrupts are handled.
> Especially hdq_reset_irqstatus.
> 
> So I will add a printk to hdq_reset_irqstatus
> to see what value it had before being reset.

I now did check the log during boot and there is the
reverse situation. Initially it works but suddenly
hdq_isr becomes 6 and then trouble starts.

So the key problem is that both, the RX and the TX
interrupts may be set and then, the code resets
everything to 0 and looses either one.

I wonder if that is an issue by two processes reading
hdq in parallel.

Another question is how independent command-writes + result-reads
are properly serialized and locked so that they don't overlap?

Maybe this is handled outside of the omap_hdq code.

So what could be a fix?

BR,
Nikolaus
 
[   17.026916] omap_hdq 480b2000.1w: omap_hdq_probe
[   17.057739] omap_hdq 480b2000.1w: omap_hdq_probe 1
[   17.062866] omap_hdq 480b2000.1w: omap_hdq_runtime_resume
[   17.221374] omap_hdq 480b2000.1w: OMAP HDQ Hardware Rev 0.5. Driver in Interrupt mode
[   17.350860] omap_hdq 480b2000.1w: omap_hdq_probe 2
[   17.372863] omap_hdq 480b2000.1w: omap_hdq_probe 3
[   17.468444] omap_hdq 480b2000.1w: hdq_isr: 1
[   17.473876] omap_hdq 480b2000.1w: Presence bit not set
[   17.505249] omap_hdq 480b2000.1w: omap_hdq_probe 4
[   17.576690] omap_hdq 480b2000.1w: omap_hdq_probe done
[   17.697998] omap_hdq 480b2000.1w: hdq_write_byte
[   17.704986] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.734954] omap_hdq 480b2000.1w: hdq_read_byte
[   17.747528] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.752044] omap_hdq 480b2000.1w: hdq_write_byte
[   17.759033] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.774414] omap_hdq 480b2000.1w: hdq_read_byte
[   17.798767] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.803314] omap_hdq 480b2000.1w: hdq_write_byte
[   17.821807] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.826385] omap_hdq 480b2000.1w: hdq_read_byte
[   17.837646] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.842224] omap_hdq 480b2000.1w: hdq_write_byte
[   17.849212] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.861877] omap_hdq 480b2000.1w: hdq_read_byte
[   17.887573] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.892150] omap_hdq 480b2000.1w: hdq_write_byte
[   17.899139] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.903686] omap_hdq 480b2000.1w: hdq_read_byte
[   17.926177] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.945434] omap_hdq 480b2000.1w: hdq_write_byte
[   17.953979] omap_hdq 480b2000.1w: hdq_isr: 4
[   17.959503] omap_hdq 480b2000.1w: hdq_read_byte
[   17.964294] omap_hdq 480b2000.1w: hdq_isr: 2
[   17.984436] omap_hdq 480b2000.1w: hdq_write_byte
[   18.017578] omap_hdq 480b2000.1w: hdq_isr: 6
[   18.022521] omap_hdq 480b2000.1w: hdq_read_byte
[   18.027282] omap_hdq 480b2000.1w: hdq_isr: 0
[   18.287597] omap_hdq 480b2000.1w: timeout waiting for RXCOMPLETE, 0
[   18.294250] omap_hdq 480b2000.1w: hdq_write_byte
[   18.313720] omap_hdq 480b2000.1w: hdq_isr: 0
[   18.537536] omap_hdq 480b2000.1w: TX wait elapsed
[   18.542510] omap_hdq 480b2000.1w: TX failure:Ctrl status 0
[   18.577697] omap_hdq 480b2000.1w: hdq_read_byte
[   18.582489] omap_hdq 480b2000.1w: hdq_isr: 0
[   18.787597] omap_hdq 480b2000.1w: timeout waiting for RXCOMPLETE, 0

  reply	other threads:[~2020-04-25 10:37 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-17  0:40 [PATCHv3] w1: omap-hdq: Simplify driver with PM runtime autosuspend Tony Lindgren
2020-04-16 15:02 ` H. Nikolaus Schaller
2020-04-16 18:46   ` Tony Lindgren
2020-04-16 20:04     ` Andreas Kemnade
2020-04-16 20:33       ` Tony Lindgren
2020-04-17 14:21         ` H. Nikolaus Schaller
2020-04-17 14:22     ` H. Nikolaus Schaller
2020-04-17 14:43       ` Andreas Kemnade
2020-04-17 14:52         ` H. Nikolaus Schaller
2020-04-17 15:07           ` Tony Lindgren
2020-04-17 15:14             ` Tony Lindgren
2020-04-17 15:36               ` Andreas Kemnade
2020-04-17 21:03             ` H. Nikolaus Schaller
2020-04-20 15:08               ` Tony Lindgren
2020-04-20 21:11                 ` H. Nikolaus Schaller
2020-04-21  6:53                   ` Andreas Kemnade
2020-04-21 18:02                     ` Tony Lindgren
2020-04-21 18:13                       ` H. Nikolaus Schaller
2020-04-21 18:20                         ` Tony Lindgren
2020-04-21 18:24                           ` Andreas Kemnade
2020-04-21 20:40                           ` H. Nikolaus Schaller
2020-04-22 10:04                             ` Andreas Kemnade
2020-04-22 16:06                               ` H. Nikolaus Schaller
     [not found]                                 ` <A2AC3E81-49B2-4CF2-A7CF-6075AEB1B72D@goldelico.com>
2020-04-25 10:29                                   ` H. Nikolaus Schaller
2020-04-25 10:37                                     ` H. Nikolaus Schaller [this message]
2020-04-29 21:34                                       ` H. Nikolaus Schaller
2020-04-29 21:38                                         ` Tony Lindgren
2020-05-09 11:47                                           ` H. Nikolaus Schaller
2020-05-09 13:59                                             ` Tony Lindgren

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