Op 08-02-18 om 19:27 schreef Ville Syrjälä: > On Thu, Feb 08, 2018 at 09:55:38AM +0100, Maarten Lankhorst wrote: >> References: https://bugs.freedesktop.org/show_bug.cgi?id=104975 >> Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com> >> --- >> drivers/gpu/drm/i915/i915_drv.h | 2 ++ >> drivers/gpu/drm/i915/i915_reg.h | 3 +++ >> drivers/gpu/drm/i915/intel_display.c | 1 + >> drivers/gpu/drm/i915/intel_sprite.c | 16 ++++++++++++++++ >> 4 files changed, 22 insertions(+) >> >> diff --git a/drivers/gpu/drm/i915/i915_drv.h >> b/drivers/gpu/drm/i915/i915_drv.h >> index d5e695da2fc4..11251e0107f4 100644 >> --- a/drivers/gpu/drm/i915/i915_drv.h >> +++ b/drivers/gpu/drm/i915/i915_drv.h >> @@ -1967,6 +1967,8 @@ struct drm_i915_private { >> /* Display functions */ >> struct drm_i915_display_funcs display; >> >> + spinlock_t display_evasion_lock; >> + >> /* PCH chipset type */ >> enum intel_pch pch_type; >> unsigned short pch_id; >> diff --git a/drivers/gpu/drm/i915/i915_reg.h >> b/drivers/gpu/drm/i915/i915_reg.h >> index 93f6ec2ea8f2..20af56644844 100644 >> --- a/drivers/gpu/drm/i915/i915_reg.h >> +++ b/drivers/gpu/drm/i915/i915_reg.h >> @@ -6594,6 +6594,9 @@ enum { >> #define DIGITAL_PORTA_HOTPLUG_SHORT_DETECT (1 << 0) >> #define DIGITAL_PORTA_HOTPLUG_LONG_DETECT (2 << 0) >> >> +#define DOUBLE_BUFFER_CTL _MMIO(0x44500) >> +#define DOUBLE_BUFFER_CTL_GLOBAL_DISABLE (1 << 0) >> + >> /* refresh rate hardware control */ >> #define RR_HW_CTL _MMIO(0x45300) >> #define RR_HW_LOW_POWER_FRAMES_MASK 0xff >> diff --git a/drivers/gpu/drm/i915/intel_display.c >> b/drivers/gpu/drm/i915/intel_display.c >> index 707406d1bf57..81087722bc49 100644 >> --- a/drivers/gpu/drm/i915/intel_display.c >> +++ b/drivers/gpu/drm/i915/intel_display.c >> @@ -14476,6 +14476,7 @@ int intel_modeset_init(struct drm_device *dev) >> dev_priv->modeset_wq = alloc_ordered_workqueue("i915_modeset", 0); >> >> drm_mode_config_init(dev); >> + spin_lock_init(&dev_priv->display_evasion_lock); >> >> dev->mode_config.min_width = 0; >> dev->mode_config.min_height = 0; >> diff --git a/drivers/gpu/drm/i915/intel_sprite.c >> b/drivers/gpu/drm/i915/intel_sprite.c >> index ac0a4f9c1954..4d1e9b166d57 100644 >> --- a/drivers/gpu/drm/i915/intel_sprite.c >> +++ b/drivers/gpu/drm/i915/intel_sprite.c >> @@ -98,6 +98,13 @@ void intel_pipe_update_start(const struct >> intel_crtc_state *new_crtc_state) >> intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI); >> DEFINE_WAIT(wait); >> >> + if (INTEL_GEN(dev_priv) >= 9) { >> + spin_lock_irq(&dev_priv->display_evasion_lock); >> + I915_WRITE(DOUBLE_BUFFER_CTL, DOUBLE_BUFFER_CTL_GLOBAL_DISABLE); >> + scanline = intel_get_crtc_scanline(crtc); >> + goto done; >> + } > I think we still want to do the vblank evasion. It gives us more accurate > infromation on which frame the operation will complete. If we don't do > it we may end up signalling the completion one frame late. Although I > suppose it doesn't matter too much from the user POV since in each case > we'd end up dropping a frame. Maybe for av sync etc. it might matter > in some cases. > > It would become even more important if we allowed flips to be overridden > because then we'd really need to know whether the previous flip happened > at all or not (so that we could signal fences and whatnot correctly to > keep userspace informed on which framebuffer is actually being scanned > out). And we might end up holding the lock across every vblank start, > thus preventing the display from updating at all. > > So I think we should use DOUBLE_BUFFER_CTL just make missing the > deadline bit less dangerous in the presence of fragile hardware. I do > think we should still try to optimize plane/pipe updates more to reduce > the chances of that happening in general. > > Also IIRC there are some "(dis)allow double buffer disable" bits in various > hardware blocks which have to set correctly for this to work. Did you check > whether we're setting them appropriately? The global switch doesn't mention this at least. It only mentions that async MMIO and command flips are not affected.
~Maarten _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
