[PATCH v4 3/4] drm/radeon: Raise msi_addr_mask to dma_bits

Vivian Wang
2026-01-29T01:56:53Z

The code was originally written using no_64bit_msi, which restricts the
device to 32-bit MSI addresses.

Since msi_addr_mask is introduced, use DMA_BIT_MASK(dma_bits) instead of
DMA_BIT_MASK(32) here for msi_addr_mask, describing the restriction more
precisely and allowing these devices to work on platforms with MSI
doorbell address above the 32-bit limit, as long as it is within the
hardware's addressable range.

Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>

---
v4: Patch message rewording for more consistency
---
drivers/gpu/drm/radeon/radeon_device.c | 1 +
drivers/gpu/drm/radeon/radeon_irq_kms.c | 10 ----------
2 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 60afaa8e56b4..5faae0361361 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1374,6 +1374,7 @@ int radeon_device_init(struct radeon_device *rdev,
pr_warn("radeon: No suitable DMA available\n");
return r;
}
+ rdev->pdev->msi_addr_mask = DMA_BIT_MASK(dma_bits);
rdev->need_swiotlb = drm_need_swiotlb(dma_bits);

/* Registers mapping */
diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
index d550554a6f3f..839d619e5602 100644
--- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
@@ -245,16 +245,6 @@ static bool radeon_msi_ok(struct radeon_device *rdev)
if (rdev->flags & RADEON_IS_AGP)
return false;

- /*
- * Older chips have a HW limitation, they can only generate 40 bits
- * of address for "64-bit" MSIs which breaks on some platforms, notably
- * IBM POWER servers, so we limit them
- */
- if (rdev->family < CHIP_BONAIRE) {
- dev_info(rdev->dev, "radeon: MSI limited to 32-bit\n");
- rdev->pdev->msi_addr_mask = DMA_BIT_MASK(32);
- }
-
/* force MSI on */
if (radeon_msi == 1)
return true;

--
2.52.0