| Message ID | 20210927121958.941637-1-arnd@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | drm/amdgpu: fix clang out-of-range warning | expand |
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; > } >
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
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; }