Hi, On Tue, Feb 15, 2011 at 01:25:34PM +0200, Tomi Valkeinen wrote: > > On Tue, Feb 15, 2011 at 10:37:37AM +0200, Tomi Valkeinen wrote: > > > > This approach looks clean, but isn't IRQF_SHARED used the other way > > > > around. One irq line and multiple handlers? > > > > > > That is the case here, isn't it (on omap3)? One interrupt line (the DSS > > > irq, the same returned both from dsi.pdev and dispc.pdev), and two > > > handlers, one in dispc and one in dsi? Or what do you mean? > > > > IMO, for omap3 it would be better to have irq_chip there. Then you can > > keep e.g. DISPC IRQ disabled until dispc.c calls request_irq(). What > > happens today if you have IRQ enabled but dispc isn't ready to act on > > those ? > > Currently we have a single interrupt handler, which then calls either > dispc and/or dsi handler. Dispc and dsi are always ready to handle > those. Exactly the kind of thing irq_chip would help you :-) > I don't think it would be a good solution if irq_chip would be used only > for omap3. Then we'd have totally different solutions for different omap > versions. But if irq_chip can be easily used for all omap versions, then > perhaps. But the HW is different anyway. On OMAP3 you're connect to a DSS irq demuxer, on OMAP4 you have dedicated lines straight from OMAP's INTC. > > > On omap2 there's no dsi code ran, so dispc is the only one requesting > > > the irq, and thus IRQF_SHARED is extra. In omap4 there are separate irq > > > lines (dsi.pdev and dispc.pdev return different irqs), and so > > > IRQF_SHARED is again extra. But I don't see any harm in IRQF_SHARED even > > > in omap2/4. > > > > What if another HW requests the wrong IRQ number and it ends up being > > your dispc IRQ line ? > > Are you asking what happens if we have a bug in kernel code? Anything > can happen =). But I don't see that as a reason not to use IRQF_SHARED. ok, I have to agree. :-) But you will be allowing for that to happen. If you don't IRQF_SHARED, request_irq() will fail on the second call with -EBUSY I believe. -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
