2021-08-13 09:08:33

by zhaoxiao

Subject: [PATCH] drm: radeon: r600_dma: Replace cpu_to_le32() by lower_32_bits()

This patch fixes the following sparse errors:
drivers/gpu/drm/radeon/r600_dma.c:247:30: warning: incorrect type in assignment (different base types)
drivers/gpu/drm/radeon/r600_dma.c:247:30: expected unsigned int volatile [usertype]
drivers/gpu/drm/radeon/r600_dma.c:247:30: got restricted __le32 [usertype]

Signed-off-by: zhaoxiao <[email protected]>
---
drivers/gpu/drm/radeon/r600_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/r600_dma.c b/drivers/gpu/drm/radeon/r600_dma.c
index fb65e6fb5c4f..a2d0b1edcd22 100644
--- a/drivers/gpu/drm/radeon/r600_dma.c
+++ b/drivers/gpu/drm/radeon/r600_dma.c
@@ -244,7 +244,7 @@ int r600_dma_ring_test(struct radeon_device *rdev,
gpu_addr = rdev->wb.gpu_addr + index;

tmp = 0xCAFEDEAD;
- rdev->wb.wb[index/4] = cpu_to_le32(tmp);
+ rdev->wb.wb[index/4] = lower_32_bits(tmp);

r = radeon_ring_lock(rdev, ring, 4);
if (r) {
--
2.20.1

2021-08-13 15:07:35

by Michel Dänzer

Subject: Re: [PATCH] drm: radeon: r600_dma: Replace cpu_to_le32() by lower_32_bits()

On 2021-08-13 10:54 a.m., zhaoxiao wrote:
> This patch fixes the following sparse errors:
> drivers/gpu/drm/radeon/r600_dma.c:247:30: warning: incorrect type in assignment (different base types)
> drivers/gpu/drm/radeon/r600_dma.c:247:30: expected unsigned int volatile [usertype]
> drivers/gpu/drm/radeon/r600_dma.c:247:30: got restricted __le32 [usertype]
>
> Signed-off-by: zhaoxiao <[email protected]>
> ---
> drivers/gpu/drm/radeon/r600_dma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/radeon/r600_dma.c b/drivers/gpu/drm/radeon/r600_dma.c
> index fb65e6fb5c4f..a2d0b1edcd22 100644
> --- a/drivers/gpu/drm/radeon/r600_dma.c
> +++ b/drivers/gpu/drm/radeon/r600_dma.c
> @@ -244,7 +244,7 @@ int r600_dma_ring_test(struct radeon_device *rdev,
> gpu_addr = rdev->wb.gpu_addr + index;
>
> tmp = 0xCAFEDEAD;
> - rdev->wb.wb[index/4] = cpu_to_le32(tmp);
> + rdev->wb.wb[index/4] = lower_32_bits(tmp);
>
> r = radeon_ring_lock(rdev, ring, 4);
> if (r) {
>

Seems better to mark rdev->wb.wb as little endian instead. It's read with le32_to_cpu (with some exceptions which look like bugs), which would result in 0xADEDFECA like this.


--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and X developer

2021-08-16 12:49:06

by Christian König

Subject: Re: [PATCH] drm: radeon: r600_dma: Replace cpu_to_le32() by lower_32_bits()

Am 13.08.21 um 17:03 schrieb Michel Dänzer:
> On 2021-08-13 10:54 a.m., zhaoxiao wrote:
>> This patch fixes the following sparse errors:
>> drivers/gpu/drm/radeon/r600_dma.c:247:30: warning: incorrect type in assignment (different base types)
>> drivers/gpu/drm/radeon/r600_dma.c:247:30: expected unsigned int volatile [usertype]
>> drivers/gpu/drm/radeon/r600_dma.c:247:30: got restricted __le32 [usertype]
>>
>> Signed-off-by: zhaoxiao <[email protected]>
>> ---
>> drivers/gpu/drm/radeon/r600_dma.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/r600_dma.c b/drivers/gpu/drm/radeon/r600_dma.c
>> index fb65e6fb5c4f..a2d0b1edcd22 100644
>> --- a/drivers/gpu/drm/radeon/r600_dma.c
>> +++ b/drivers/gpu/drm/radeon/r600_dma.c
>> @@ -244,7 +244,7 @@ int r600_dma_ring_test(struct radeon_device *rdev,
>> gpu_addr = rdev->wb.gpu_addr + index;
>>
>> tmp = 0xCAFEDEAD;
>> - rdev->wb.wb[index/4] = cpu_to_le32(tmp);
>> + rdev->wb.wb[index/4] = lower_32_bits(tmp);
>>
>> r = radeon_ring_lock(rdev, ring, 4);
>> if (r) {
>>
> Seems better to mark rdev->wb.wb as little endian instead. It's read with le32_to_cpu (with some exceptions which look like bugs), which would result in 0xADEDFECA like this.

Yeah, that patch doesn't look correct at all and most likely breaks ring
test on big endian systems.

Christian.