linux-kernel - Re: [RESEND PATCH] gpio: omap: Fix lost edge interrupts

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Date:   Tue, 3 Oct 2017 11:52:01 -0500
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Santosh Shilimkar <santosh.shilimkar@...cle.com>
CC:     Linus Walleij <linus.walleij@...aro.org>,
        Tony Lindgren <tony@...mide.com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        <linux-omap@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Ladislav Michl <ladis@...ux-mips.org>
Subject: Re: [RESEND PATCH] gpio: omap: Fix lost edge interrupts

Hi Santosh,

On 10/03/2017 11:41 AM, Santosh Shilimkar wrote:
> 
> 
> On 10/3/2017 9:17 AM, Grygorii Strashko wrote:
>> Now acking of edge irqs happens the following way:
>> - omap_gpio_irq_handler
>>    - "isr" = read irq status
>>    - omap_clear_gpio_irqbank(bank, isr_saved & ~level_mask);
>>     ^ clear edge status, so irq can be accepted
>>    - loop while "isr"
>>     generic_handle_irq()
>>      - handle_edge_irq()
>>         - desc->irq_data.chip->irq_ack(&desc->irq_data);
>>         - omap_gpio_ack_irq()
>> it might be that at this moment edge IRQ was triggered again and it 
>> will be
>> cleared and IRQ will be lost.
>>
>> Use handle_simple_irq and clear edge interrupts early without 
>> disabling them in
>> omap_gpio_irq_handler to avoid loosing interrupts.
>>
>> [1] 
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__marc.info_-3Fl-3Dlinux-2Domap-26m-3D149004465313534-26w-3D2&d=DwIBAg&c=RoP1YumCXCgaWHvlZYR8PQcxBKCX5YTpkKY057SbK10&r=XBn1JQGPwR8CsE7xpP3wPlG6DQU7qw8ym65xieNZ4hY&m=-JZAaXlsRBFYNqtZ-2KOemoupa4pL7ka9D3wKn6hX9o&s=c-1XuQUl3_1uYedoNhmY70xCO3fAftWB7cmFxgyC3j4&e= 
>>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
>> Signed-off-by: Ladislav Michl <ladis@...ux-mips.org>
>> ---
>> Resend with proper cc list.
>>
> This was one of the concern I was thinking when GPIO IRQ conversion
> was done. Grygorii since you did that conversion, can you please
> check since I see now that the irq code is becoming increasingly
> complex.

This patch was developed in coop with Ladislav and he intensively tested it and
this patch actually simplifies IRQ handling. Also, OMAP driver parts which
this patch touches are ancient. 

 

-- 
regards,
-grygorii