diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_pm.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index d8fb00a2b565..3cd521f3823b 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -30,6 +30,7 @@ #include "intel_drv.h" #include "../../../platform/x86/intel_ips.h" #include <linux/module.h> +#include <linux/vgaarb.h> #include <drm/i915_powerwell.h> #include <linux/pm_runtime.h> @@ -5686,6 +5687,20 @@ static void hsw_power_well_post_enable(struct drm_i915_private *dev_priv) struct drm_device *dev = dev_priv->dev; unsigned long irqflags; + /* + * After we re-enable the power well, if we touch VGA register 0x3d5 + * we'll get unclaimed register interrupts. This stops after we write + * anything to the VGA MSR register. The vgacon module uses this + * register all the time, so if we unbind our driver and, as a + * consequence, bind vgacon, we'll get stuck in an infinite loop at + * console_unlock(). So make here we touch the VGA MSR register, making + * sure vgacon can keep working normally without triggering interrupts + * and error messages. + */ + vga_get_uninterruptible(dev->pdev, VGA_RSRC_LEGACY_IO); + outb(inb(VGA_MSR_READ), VGA_MSR_WRITE); + vga_put(dev->pdev, VGA_RSRC_LEGACY_IO); + if (IS_BROADWELL(dev)) { spin_lock_irqsave(&dev_priv->irq_lock, irqflags); I915_WRITE(GEN8_DE_PIPE_IMR(PIPE_B), |