linux-kernel - Re: [PATCH] media: vsp1: mask interrupts before enabling

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Date:   Tue, 02 Nov 2021 11:13:47 +0000
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>
Cc:     linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Koji Matsuoka <koji.matsuoka.xm@...esas.com>
Subject: Re: [PATCH] media: vsp1: mask interrupts before enabling

Quoting Nikita Yushchenko (2021-10-20 18:45:50)
> Hi,
> 
> > Could you test to see if those lines to explicitly set VI6_DISP_IRQ_ENB
> > and VI6_WPF_IRQ_ENB are really needed in your use case please?
> 
> Commenting out those register writes causes
> 
> [    2.275137][    C0] irq 188: nobody cared (try booting with the "irqpoll" option)
> [    2.282621][    C0] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc5 #28

Ok, so something has clearly caused these to get set, and the reset has
not cleared them.

I think I would rather see the code to reset them done in
vsp1_reset_wpf(), rather than in probe directly as that is what we are
doing, and is I believe already in the call path.

This should be with a comment stating explicitly that we are manually
resetting VI6_DISP_IRQ_ENB as the reset does not always clear these
bits.

(But I'm reallly ... reallly concerned that the hardware is not really
getting reset when it should, and that might merit some further
investigation).

Requesting the devm_request_irq() /after/ initialising the hardware is
certainly a good thing though.

--
Kieran



> [    2.289669][    C0] Hardware name: Renesas H3ULCB Kingfisher board based on r8a77951 (DT)
> [    2.297844][    C0] Call trace:
> [    2.300981][    C0]  dump_backtrace+0x0/0x198
> [    2.305348][    C0]  show_stack+0x1c/0x28
> [    2.309357][    C0]  dump_stack_lvl+0x64/0x7c
> [    2.313718][    C0]  dump_stack+0x14/0x2c
> [    2.317725][    C0]  __report_bad_irq+0x50/0xdc
> [    2.322254][    C0]  note_interrupt+0x2e4/0x330
> [    2.326786][    C0]  handle_irq_event_percpu+0x58/0x68
> [    2.331927][    C0]  handle_irq_event+0x4c/0x98
> [    2.336456][    C0]  handle_fasteoi_irq+0xd0/0x180
> [    2.341245][    C0]  handle_domain_irq+0x94/0xd8
> [    2.345862][    C0]  gic_handle_irq+0xa4/0xe0
> [    2.350216][    C0]  do_interrupt_handler+0x38/0x60
> [    2.355093][    C0]  el1_interrupt+0x2c/0x68
> [    2.359362][    C0]  el1h_64_irq_handler+0x14/0x20
> [    2.364151][    C0]  el1h_64_irq+0x74/0x78
> [    2.368244][    C0]  __do_softirq+0xc8/0x404
> [    2.372511][    C0]  irq_exit+0x118/0x140
> [    2.376521][    C0]  handle_domain_irq+0x98/0xd8
> [    2.381137][    C0]  gic_handle_irq+0xa4/0xe0
> [    2.385490][    C0]  call_on_irq_stack+0x28/0x3c
> [    2.390105][    C0]  do_interrupt_handler+0x54/0x60
> [    2.394981][    C0]  el1_interrupt+0x2c/0x68
> [    2.399247][    C0]  el1h_64_irq_handler+0x14/0x20
> [    2.404036][    C0]  el1h_64_irq+0x74/0x78
> [    2.408129][    C0]  _raw_spin_unlock_irqrestore+0x20/0x50
> [    2.413615][    C0]  __setup_irq+0x56c/0x888
> [    2.417882][    C0]  request_threaded_irq+0xf0/0x1a8
> [    2.422843][    C0]  devm_request_threaded_irq+0x84/0xf8
> [    2.428155][    C0]  vsp1_probe+0x218/0xb48
> [    2.432340][    C0]  platform_probe+0x6c/0xd8
> [    2.436700][    C0]  really_probe+0xc0/0x428
> [    2.440967][    C0]  __driver_probe_device+0x114/0x188
> [    2.446103][    C0]  driver_probe_device+0x44/0xe8
> [    2.450891][    C0]  __driver_attach+0xbc/0x1a0
> [    2.455419][    C0]  bus_for_each_dev+0x64/0xa0
> [    2.459947][    C0]  driver_attach+0x28/0x30
> [    2.464215][    C0]  bus_add_driver+0x144/0x228
> [    2.468743][    C0]  driver_register+0x68/0x118
> [    2.473272][    C0]  __platform_driver_register+0x2c/0x38
> [    2.478669][    C0]  vsp1_platform_driver_init+0x20/0x28
> [    2.483985][    C0]  do_one_initcall+0x38/0x258
> [    2.488513][    C0]  kernel_init_freeable+0x228/0x28c
> [    2.493565][    C0]  kernel_init+0x28/0x120
> [    2.497745][    C0]  ret_from_fork+0x10/0x20
> [    2.502013][    C0] handlers:
> [    2.504974][    C0] [<0000000040be598b>] vsp1_irq_handler
> [    2.510376][    C0] Disabling IRQ #188
> 
> Nikita