drm/i915: Pre-populate the cursor physical dma address

[ Upstream commit 582dc04b0658ef3b90aeb49cbdd9747c2f1eccc3 ]

Calling i915_gem_object_get_dma_address() from the vblank
evade critical section triggers might_sleep().

While we know that we've already pinned the framebuffer
and thus i915_gem_object_get_dma_address() will in fact
not sleep in this case, it seems reasonable to keep the
unconditional might_sleep() for maximum coverage.

So let's instead pre-populate the dma address during
fb pinning, which all happens before we enter the
vblank evade critical section.

We can use u32 for the dma address as this class of
hardware doesn't support >32bit addresses.

Cc: stable@vger.kernel.org
Fixes: 0225a90981c8 ("drm/i915: Make cursor plane registers unlocked")
Reported-by: Borislav Petkov <bp@alien8.de>
Closes: https://lore.kernel.org/intel-gfx/20240227100342.GAZd2zfmYcPS_SndtO@fat_crate.local/
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240325175738.3440-1-ville.syrjala@linux.intel.com
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
(cherry picked from commit c1289a5c3594cf04caa94ebf0edeb50c62009f1f)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
index 0d21c34f74990efee414dcc0c01e5b0a9456127c..61df6cd3f37788a5e1b1d45ec9765563d93c486e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_cursor.c
+++ b/drivers/gpu/drm/i915/display/intel_cursor.c
@@ -34,12 +34,10 @@ static u32 intel_cursor_base(const struct intel_plane_state *plane_state)
 {
        struct drm_i915_private *dev_priv =
                to_i915(plane_state->uapi.plane->dev);
-       const struct drm_framebuffer *fb = plane_state->hw.fb;
-       struct drm_i915_gem_object *obj = intel_fb_obj(fb);
        u32 base;
 
        if (DISPLAY_INFO(dev_priv)->cursor_needs_physical)
-               base = i915_gem_object_get_dma_address(obj, 0);
+               base = plane_state->phys_dma_addr;
        else
                base = intel_plane_ggtt_offset(plane_state);
 

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 7fc92b1474cc423f3f26afc49ca19201c532b7fd..8b0dc2b75da4a9116d1e1cfdee8986b7f25f5788 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -701,6 +701,7 @@ struct intel_plane_state {
 #define PLANE_HAS_FENCE BIT(0)
 
        struct intel_fb_view view;
+       u32 phys_dma_addr; /* for cursor_needs_physical */
 
        /* Plane pxp decryption state */
        bool decrypt;

diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c b/drivers/gpu/drm/i915/display/intel_fb_pin.c
index fffd568070d4141c5c3f7b7f0e1d220f1e0481c7..a131656757f2b69a497405b1b8c3862121a166ee 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
+++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
@@ -254,6 +254,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
                        return PTR_ERR(vma);
 
                plane_state->ggtt_vma = vma;
+
+               /*
+                * Pre-populate the dma address before we enter the vblank
+                * evade critical section as i915_gem_object_get_dma_address()
+                * will trigger might_sleep() even if it won't actually sleep,
+                * which is the case when the fb has already been pinned.
+                */
+               if (phys_cursor)
+                       plane_state->phys_dma_addr =
+                               i915_gem_object_get_dma_address(intel_fb_obj(fb), 0);
        } else {
                struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);