[Intel-gfx] [PATCH v2 4/9] drm/i915/fbdev: lock the fbdev obj before vma pin

[Radhakrishna Sripada]

From: Tejas Upadhyay <tejas.upadh...@intel.com>

lock the fbdev obj before calling into
i915_vma_pin_iomap(). This helps to solve below :

<7>[   93.563308] i915 0000:00:02.0: [drm:intelfb_create [i915]] no BIOS fb, 
allocating a new one
<4>[   93.581844] ------------[ cut here ]------------
<4>[   93.581855] WARNING: CPU: 12 PID: 625 at 
drivers/gpu/drm/i915/gem/i915_gem_pages.c:424 
i915_gem_object_pin_map+0x152/0x1c0 [i915]

Fixes: b473df22760f9 ("backport "drm/i915: Add ww context to intel_dpt_pin, 
v2.")
Cc: Chris Wilson <chris.p.wil...@intel.com>
Cc: Matthew Auld <matthew.a...@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadh...@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.srip...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbdev.c | 24 ++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c 
b/drivers/gpu/drm/i915/display/intel_fbdev.c
index 3659350061a7..2766d7ef0128 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -210,6 +210,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
        bool prealloc = false;
        void __iomem *vaddr;
        struct drm_i915_gem_object *obj;
+       struct i915_gem_ww_ctx ww;
        int ret;
 
        mutex_lock(&ifbdev->hpd_lock);
@@ -283,13 +284,24 @@ static int intelfb_create(struct drm_fb_helper *helper,
                info->fix.smem_len = vma->size;
        }
 
-       vaddr = i915_vma_pin_iomap(vma);
-       if (IS_ERR(vaddr)) {
-               drm_err(&dev_priv->drm,
-                       "Failed to remap framebuffer into virtual memory 
(%pe)\n", vaddr);
-               ret = PTR_ERR(vaddr);
-               goto out_unpin;
+       for_i915_gem_ww(&ww, ret, false) {
+               ret = i915_gem_object_lock(vma->obj, &ww);
+
+               if (ret)
+                       continue;
+
+               vaddr = i915_vma_pin_iomap(vma);
+               if (IS_ERR(vaddr)) {
+                       drm_err(&dev_priv->drm,
+                                       "Failed to remap framebuffer into 
virtual memory (%pe)\n", vaddr);
+                       ret = PTR_ERR(vaddr);
+                       continue;
+               }
        }
+
+       if (ret)
+               goto out_unpin;
+
        info->screen_base = vaddr;
        info->screen_size = vma->size;
 
-- 
2.34.1