Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-29 06:12:08 +00:00
Code Issues Packages Projects Releases Wiki Activity

drm/i915/chv: Ack interrupts before handling them (CHV)

Browse Source 
Otherwise, we might receive a new interrupt before we have time to
ack the first one, eventually missing it.

Without an atomic XCHG operation with mmio space, this patch merely
reduces the window in which we can miss an interrupt (especially when
you consider how heavyweight the I915_READ/I915_WRITE operations are).

Notice that, before clearing a port-sourced interrupt in the IIR, the
corresponding interrupt source status in the PORT_HOTPLUG_STAT must be
cleared.

Spotted by Bob Beckett <robert.beckett@intel.com>.

v2:
- Add warning to commit message and comments to the code as per Chris
  Wilson's request.
- Imre Deak pointed out that the pipe underrun flag might not be signaled
  in IIR, so do not make valleyview_pipestat_irq_handler depend on it.

v3: Improve the source code comment.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Oscar Mateo 2014-06-16 16:11:00 +01:00 committed by Daniel Vetter
parent 38cc46d73e
commit 27b6c12251
1 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/gpu/drm/i915/i915_irq.c
View File

@ -1898,21 +1898,27 @@ static irqreturn_t cherryview_irq_handler(int irq, void *arg)
if (master_ctl == 0 && iir == 0)
break;
ret = IRQ_HANDLED;
I915_WRITE(GEN8_MASTER_IRQ, 0);
/* Find, clear, then process each source of interrupt */
if (iir) {
/* Consume port before clearing IIR or we'll miss events */
if (iir & I915_DISPLAY_PORT_INTERRUPT)
i9xx_hpd_irq_handler(dev);
I915_WRITE(VLV_IIR, iir);
}
gen8_gt_irq_handler(dev, dev_priv, master_ctl);
/* Call regardless, as some status bits might not be
* signalled in iir */
valleyview_pipestat_irq_handler(dev, iir);
/* Consume port. Then clear IIR or we'll miss events */
i9xx_hpd_irq_handler(dev);
I915_WRITE(VLV_IIR, iir);
I915_WRITE(GEN8_MASTER_IRQ, DE_MASTER_IRQ_CONTROL);
POSTING_READ(GEN8_MASTER_IRQ);
ret = IRQ_HANDLED;
}
return ret;