[PATCH] drm/lima: call drm_mm_init() with a valid allocation range

[Henrik Grimler]

lima_vm_create() is currently run before va_start and va_end are set up,
meaning they are both 0. lima_vm_create() runs drm_mm_init() with them
as arguments for the allocator, and if DRM_DEBUG_MM is enabled the
DRM_MM_BUG_ON check in drm_mm_init then fires, as seen here on
exynos4412-odroid-u2:

[    1.736297] ------------[ cut here ]------------
[    1.740370] kernel BUG at drivers/gpu/drm/drm_mm.c:931!
[    1.745574] Internal error: Oops - BUG: 0 [#1] SMP ARM
[    1.750697] Modules linked in:
[    1.753734] CPU: 0 UID: 0 PID: 41 Comm: kworker/u16:1 Not tainted 7.0.10-postmarketos-exynos4 #11 PREEMPT
[    1.763372] Hardware name: Samsung Exynos (Flattened Device Tree)
[    1.769446] Workqueue: events_unbound deferred_probe_work_func
[    1.775261] PC is at drm_mm_init+0x9c/0xa4
[    1.779339] LR is at lima_vm_create+0x144/0x17c
[ ... ]

Fix the issue by moving the lima_vm_create() call after va_start and
va_end are set up.

Fixes: a1d2a6339961 ("drm/lima: driver for ARM Mali4xx GPUs")
Signed-off-by: Henrik Grimler <henrik.grimler@xxxxxxxx>
---
This is a low priority fix and can wait for v7.2, it does not cause
any real issues as far as I have seen: drm_mm_init() is re-run some
seconds after first run with correct parameters.
---
 drivers/gpu/drm/lima/lima_device.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/lima/lima_device.c b/drivers/gpu/drm/lima/lima_device.c
index 0bf7105c8748..7c873e62c16d 100644
--- a/drivers/gpu/drm/lima/lima_device.c
+++ b/drivers/gpu/drm/lima/lima_device.c
@@ -368,12 +368,6 @@ int lima_device_init(struct lima_device *ldev)
 	if (err)
 		goto err_out0;
 
-	ldev->empty_vm = lima_vm_create(ldev);
-	if (!ldev->empty_vm) {
-		err = -ENOMEM;
-		goto err_out1;
-	}
-
 	ldev->va_start = 0;
 	if (ldev->id == lima_gpu_mali450) {
 		ldev->va_end = LIMA_VA_RESERVE_START;
@@ -387,6 +381,12 @@ int lima_device_init(struct lima_device *ldev)
 	} else
 		ldev->va_end = LIMA_VA_RESERVE_END;
 
+	ldev->empty_vm = lima_vm_create(ldev);
+	if (!ldev->empty_vm) {
+		err = -ENOMEM;
+		goto err_out1;
+	}
+
 	ldev->iomem = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(ldev->iomem)) {
 		dev_err(ldev->dev, "fail to ioremap iomem\n");

---
base-commit: c453c60fdba437f69209e027b418c4a24143605a
change-id: 20260529-lima-alloc-fix-2cd5408f6493

Best regards,
-- 
Henrik Grimler <henrik.grimler@xxxxxxxx>