Re: Initialisation bug in IDE patch

[Andrew Pam <xanni@glasswings.com.au>]

On Tue, May 21, 2002 at 11:00:45PM -0700, Andre Hedrick wrote:
> 
> Please check the function in the top of ide.c
> 
> linux-2.4.19-p7 ide.c
> 
> static void init_hwif_data (unsigned int index)
> {
>         unsigned int unit;
>         hw_regs_t hw;
>         ide_hwif_t *hwif = &ide_hwifs[index];
> 
>         /* bulk initialize hwif & drive info with zeros */
>         memset(hwif, 0, sizeof(ide_hwif_t));
>         memset(&hw, 0, sizeof(hw_regs_t));
> 
>         /* fill in any non-zero initial values */
>         hwif->index     = index;
>         ide_init_hwif_ports(&hw, ide_default_io_base(index), 0, &hwif->irq);
>         memcpy(&hwif->hw, &hw, sizeof(hw));
>         memcpy(hwif->io_ports, hw.io_ports, sizeof(hw.io_ports));
>         hwif->noprobe   = !hwif->io_ports[IDE_DATA_OFFSET];
> 
> Obviously you are calling things outside of the normal usage of the
> driver.  

No, this is the existing driver as shipped; I have not modified the code.
The init_hwif_data roiutine has not yet been called while the ide_setup()
routine is parsing the kernel parameters, hence the bug.

> 2.2.19 ide.c
> 
> /*
>  * Do not even *think* about calling this!
>  */
> static void init_hwif_data (unsigned int index)
> {
>         unsigned int unit;
>         hw_regs_t hw;
>         ide_hwif_t *hwif = &ide_hwifs[index];
> 
>         /* bulk initialize hwif & drive info with zeros */
>         memset(hwif, 0, sizeof(ide_hwif_t));
>         memset(&hw, 0, sizeof(hw_regs_t));
> 
>         /* fill in any non-zero initial values */
>         hwif->index     = index;
>         ide_init_hwif_ports(&hw, ide_default_io_base(index), 0, &hwif->irq);
>         memcpy(&hwif->hw, &hw, sizeof(hw));
>         memcpy(hwif->io_ports, hw.io_ports, sizeof(hw.io_ports));
>         hwif->noprobe   = !hwif->io_ports[IDE_DATA_OFFSET];
> #ifdef CONFIG_BLK_DEV_HD
>         if (hwif->io_ports[IDE_DATA_OFFSET] == HD_DATA)
> 
> If you are attempting to introduce a hw.chipset which is unknown to the
> driver please submit a patch to register it or the enum index will barf.

No, I have a qd6580 which is already supported.  This bug is in existing
kernel code; I am not adding any new code, but spent some hours debugging
the problem with printk statements.

Regards,
	Andrew Pam
-- 
mailto:xanni@xanadu.net                         Andrew Pam
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