* [PATCH] drm/amdgpu: fix clang out-of-range warning
@ 2021-09-27 12:19 Arnd Bergmann
2021-09-27 12:26 ` Christian König
2021-09-28 9:56 ` Michel Dänzer
0 siblings, 2 replies; 3+ messages in thread
From: Arnd Bergmann @ 2021-09-27 12:19 UTC (permalink / raw)
To: Alex Deucher, Christian König, Pan, Xinhui, David Airlie,
Daniel Vetter
Cc: Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Evan Quan,
Hawking Zhang, Huang Rui, shaoyunl, Andrey Grodzovsky,
Jack Zhang, amd-gfx, dri-devel, linux-kernel, llvm
From: Arnd Bergmann <arnd@arndb.de>
clang-14 points out that comparing an 'unsigned int' against a large
64-bit constantn is pointless:
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1206:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
res->start > 0x100000000ull)
Rephrase the comparison using the upper_32_bits() macro, which should
keep it legible while avoiding the warning.
Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index ab3794c42d36..741a55031ca1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1203,7 +1203,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
pci_bus_for_each_resource(root, res, i) {
if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
- res->start > 0x100000000ull)
+ upper_32_bits(res->start) != 0)
break;
}
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/amdgpu: fix clang out-of-range warning
2021-09-27 12:19 [PATCH] drm/amdgpu: fix clang out-of-range warning Arnd Bergmann
@ 2021-09-27 12:26 ` Christian König
2021-09-28 9:56 ` Michel Dänzer
1 sibling, 0 replies; 3+ messages in thread
From: Christian König @ 2021-09-27 12:26 UTC (permalink / raw)
To: Arnd Bergmann, Alex Deucher, Pan, Xinhui, David Airlie, Daniel Vetter
Cc: Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Evan Quan,
Hawking Zhang, Huang Rui, shaoyunl, Andrey Grodzovsky,
Jack Zhang, amd-gfx, dri-devel, linux-kernel, llvm
In general that change looks good. But what configuration is that?
Background is that it doesn't make much sense to compile the amdgpu
driver on systems where resource_size_t is only 32bit.
Christian.
Am 27.09.21 um 14:19 schrieb Arnd Bergmann:
> From: Arnd Bergmann <arnd@arndb.de>
>
> clang-14 points out that comparing an 'unsigned int' against a large
> 64-bit constantn is pointless:
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1206:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> res->start > 0x100000000ull)
>
> Rephrase the comparison using the upper_32_bits() macro, which should
> keep it legible while avoiding the warning.
>
> Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index ab3794c42d36..741a55031ca1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -1203,7 +1203,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
>
> pci_bus_for_each_resource(root, res, i) {
> if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
> - res->start > 0x100000000ull)
> + upper_32_bits(res->start) != 0)
> break;
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/amdgpu: fix clang out-of-range warning
2021-09-27 12:19 [PATCH] drm/amdgpu: fix clang out-of-range warning Arnd Bergmann
2021-09-27 12:26 ` Christian König
@ 2021-09-28 9:56 ` Michel Dänzer
1 sibling, 0 replies; 3+ messages in thread
From: Michel Dänzer @ 2021-09-28 9:56 UTC (permalink / raw)
To: Arnd Bergmann, Alex Deucher, Christian König, Pan, Xinhui,
David Airlie, Daniel Vetter
Cc: Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Evan Quan,
Hawking Zhang, Huang Rui, shaoyunl, Andrey Grodzovsky,
Jack Zhang, amd-gfx, dri-devel, linux-kernel, llvm
On 2021-09-27 14:19, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> clang-14 points out that comparing an 'unsigned int' against a large
> 64-bit constantn is pointless:
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1206:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> res->start > 0x100000000ull)
>
> Rephrase the comparison using the upper_32_bits() macro, which should
> keep it legible while avoiding the warning.
>
> Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index ab3794c42d36..741a55031ca1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -1203,7 +1203,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
>
> pci_bus_for_each_resource(root, res, i) {
> if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
> - res->start > 0x100000000ull)
> + upper_32_bits(res->start) != 0)
New code matches 1ull << 32, old code didn't. If this difference matters, this would break if res->start is 64 bits?
--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and Xwayland developer
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-09-28 10:02 UTC | newest]
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2021-09-27 12:19 [PATCH] drm/amdgpu: fix clang out-of-range warning Arnd Bergmann
2021-09-27 12:26 ` Christian König
2021-09-28 9:56 ` Michel Dänzer
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