Hi Am 28.10.22 um 08:33 schrieb Alexander Stein:
Hi Thomas, Am Donnerstag, 27. Oktober 2022, 16:04:34 CEST schrieb Thomas Zimmermann:* PGP Signed: 10/27/2022 at 04:04:34 PM Hi Am 27.10.22 um 15:07 schrieb Alexander Stein:Hello Thomas, Am Donnerstag, 27. Oktober 2022, 13:57:06 CEST schrieb Thomas Zimmermann:Properties of 32-bit integers are returned from the OF device tree as type __be32. Cast PCI vendor and device IDs from __be32 to u32 before comparing them to constants. Fixes sparse warnings shown below. drivers/gpu/drm/tiny/ofdrm.c:237:17: warning: restricted __be32 degrades to integer drivers/gpu/drm/tiny/ofdrm.c:238:18: warning: restricted __be32 degrades to integer drivers/gpu/drm/tiny/ofdrm.c:238:54: warning: restricted __be32 degrades to integer See [1] for the bug report. Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://lore.kernel.org/dri-devel/202210192208.D888I6X7-lkp@xxxxxxxxx/ # [1] --- drivers/gpu/drm/tiny/ofdrm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/tiny/ofdrm.c b/drivers/gpu/drm/tiny/ofdrm.c index 0e1cc2369afcc..0da8b248ccc6e 100644 --- a/drivers/gpu/drm/tiny/ofdrm.c +++ b/drivers/gpu/drm/tiny/ofdrm.c @@ -231,8 +231,11 @@ static u64 display_get_address_of(struct drm_device *dev, struct device_node *of return address; } -static bool is_avivo(__be32 vendor, __be32 device) +static bool is_avivo(__be32 vendor_id, __be32 device_id) { + u32 vendor = (__force u32)vendor_id; + u32 device = (__force u32)device_id;I don't have much context, but just from reading this, shouldn't this be be32_to_cpu() instead?I should have explained that in the commit message. The values are supposed to be in big endian. We compare to PCI ids. The code originally was taken from [1], which does the right thing. The next version will add this info to the commit message. Best regards Thomas [1] https://elixir.bootlin.com/linux/v6.0.5/source/drivers/video/fbdev/offb.c#L3 57Thanks for the link. The commit message for that original change [2] indicates this was a fix on a Powerstation which happens to be a PowerPC aka big-endian. This this happens to work as intended, but not on little-endian machines. vendor_id is __be32 (big-endian) and you compare this to PCI_VENDOR_ID_ATI (0x1002) which is native-endian. I guess you see the problem. See also [3] where a property is converted properly. Thinking about it, instead of calling 'is_avivo(*vendor_p, *device_p)' I'd prefer something like 'is_avivo(be32_to_cpup(vendor_p), be32_to_cpup(device_p))', so there is no need to pass __be32 around.
Makes sense. Thanks for reviewing. Best regards Thomas
Best regards, Alexander [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ commit/?id=57a20d8fb0d2a05abe40abd6bb29e3f923721f1b [3] https://elixir.bootlin.com/linux/v6.0.5/source/drivers/bus/fsl-mc/fsl-mc-bus.c#L1027Best regards, Alexander+ /* This will match most R5xx */ return (vendor == PCI_VENDOR_ID_ATI) && ((device >= PCI_VENDOR_ID_ATI_R520 && device < 0x7800) ||
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
Attachment:
OpenPGP_signature
Description: OpenPGP digital signature
