[PATCH] pata_of_platform: fix no irq handling

[Steven A. Falco]

Anton Vorontsov wrote:
> When no irq specified, pata_of_platform fills irq_res with -1,
> which is wrong to do for two reasons:
>
> 1. By definition, 'no irq' should be IRQ 0, not some negative integer;
> 2. pata_platform checks for irq_res.start > 0, but since irq_res.start
>    is unsigned type, the check will be true for `-1'.
>
> Reported-by: Steven A. Falco <sfalco at harris.com>
> Signed-off-by: Anton Vorontsov <avorontsov at ru.mvista.com>
> ---

Thanks!  Your fix is better - I didn't really like the -1 stuff.

I found this bug because I had to disable the ATA interrupt on my system
in order to get a compact-flash card to work.  I am still trying to find
out why the interrupt doesn't work for me.  Here is part of the console
log with the interrupt enabled:

    Uniform Multi-Platform E-IDE driver
    ide: Assuming 33MHz system bus speed for PIO modes; override with
    idebus=xx
    Driver 'sd' needs updating - please use bus_type methods
    irq: irq_create_mapping(0xc0574900, 0x1b)
    irq: -> using host @c0574900
    irq: -> obtained virq 32
    scsi0 : pata_platform
    ata1: PATA max PIO4 mmio cmd 0x1c1000000 ctl 0x1c1000080 irq 32
    irq 32: nobody cared (try booting with the "irqpoll" option)
    Call Trace:
    [cf83fcc0] [c0005a64] show_stack+0x44/0x1ac (unreliable)
    [cf83fd00] [c00489e4] __report_bad_irq+0x34/0xb8
    [cf83fd20] [c0048cf0] note_interrupt+0x288/0x2d0
    [cf83fd50] [c0049a94] handle_level_irq+0xac/0x114
    [cf83fd60] [c0003df0] do_IRQ+0xa4/0xc8
    [cf83fd70] [c000d60c] ret_from_except+0x0/0x18
    [cf83fe30] [00000020] 0x20
    [cf83fe50] [c0003d48] do_softirq+0x54/0x58
    [cf83fe60] [c00241c0] irq_exit+0x90/0x94
    [cf83fe70] [c0003df4] do_IRQ+0xa8/0xc8
    [cf83fe80] [c000d60c] ret_from_except+0x0/0x18
    [cf83ff40] [c01b2cc0] ata_pio_task+0x48/0x104
    [cf83ff60] [c00307a0] run_workqueue+0xb8/0x148
    [cf83ff90] [c0030d54] worker_thread+0x70/0xd0
    [cf83ffd0] [c0034788] kthread+0x48/0x84
    [cf83fff0] [c000cd6c] kernel_thread+0x44/0x60
    handlers:
    [<c01b2d7c>] (ata_sff_interrupt+0x0/0x234)
    Disabling IRQ #32


So it looks like the ATA handler was attached - not sure yet why I got
the "nobody cared" message.  Also, the system hangs.  If I find
something, I'll post it.

    Steve


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