On Mon, Dec 11, 2017 at 08:33:33AM +0000, Anand, Jerome wrote: > > > > -----Original Message----- > > From: Thomas Gleixner [mailto:tglx@xxxxxxxxxxxxx] > > Sent: Saturday, December 9, 2017 4:22 AM > > To: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Cc: Chen, Augustine <augustine.chen@xxxxxxxxx>; intel- > > gfx@xxxxxxxxxxxxxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx; Anand, Jerome > > <jerome.anand@xxxxxxxxx>; Bossart, Pierre-louis <pierre- > > louis.bossart@xxxxxxxxx>; tiwai@xxxxxxx; Ingo Molnar <mingo@xxxxxxxxxx>; > > H. Peter Anvin <hpa@xxxxxxxxx>; Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>; Juergen > > Gross <jgross@xxxxxxxx>; Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>; linux- > > kernel@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH] drm/i915: Remove unused IRQ chip data of > > HDMI LPE audio > > > > On Fri, 8 Dec 2017, Ville Syrjälä wrote: > > > > > On Fri, Dec 08, 2017 at 05:33:23PM +0800, Augustine.Chen wrote: > > > > The chip data of HDMI LPE audio is set to drm_i915_private which is > > > > not consistent with the expectation by x86 APIC driver. > > > > > > Hmm. Why is the apic code looking at data for an irq chip it hasn't > > > created? > > > > > apic code expects an irq domain to be place as generic approach. > > > > Do we need something like > > > - dev_priv->lpe_audio.irq = irq_alloc_desc(0); > > > + dev_priv->lpe_audio.irq = irq_alloc_desc(-1); > > > > #define irq_alloc_desc(node) > > > > So instead of handing in node 0 you hand in node -1 which is NUMA_NO_NODE > > Ah. I misread the macros. So we already pass irq=-1. > > Agree - am not sure whether it will make any difference. > > > > That *looks* more correct to me based on a cursory glance at the x86 > > > code, but I didn't trawl very deeply. > > > > The x86 core cares not at all about interrupt chips which are created in a driver > > and not connected to an actual apic/ioapic/msi interrupt. This interrupt chip is > > its own thing as we have others in GPIO etc. > > > > > > In the case of not enabling CONFIG_CPUMASK_OFFSTACK, this would > > > > cause kernel panic while doing CPU hotplug. > > > > And why so? Surely not because you set irq_chip_data. That's really no > > explanation at all. > > > > Ideally, I feel there needs to be an irq domain for mapping the irq numbers with hwirq. > It is not created as part of the hdmi lpe audio bridge. > Since the logic to mask/unmask lpe audio interrupts is removed, there is no need of the > Chip data or creation of the domain now. There is no need right now. But there might be a need in the future. LPE audio isn't even the only piece of hardware whose irq goes through the i915 display engine (there's also the ISP and VED). So I would much prefer a proper solution instead of sweeping the problem under the rug. -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
