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

Christian König
2026-01-29T08:08:15Z

On 1/29/26 02:56, Vivian Wang wrote:
> 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>

Reviewed-by: Christian König <christian.koenig@amd.com>

>
> ---
> 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;
>