Hello Marek,

with powerpc64-linux-gnu-gcc, version 9.2.1, big endian I see the errors below.

struct usb_device_descriptor is naturally packed. Why do we need the packed attribute in include/linux/usb/ch9.h?

If it is needed, we should replace le16_to_cpus() by an alignment friendly implementation in common/usb.c, e.g. using u8* pointers.

CC common/usb.o In file included from ./arch/powerpc/include/asm/byteorder.h:82, from ./arch/powerpc/include/asm/bitops.h:8, from include/linux/bitops.h:136, from include/common.h:26, from common/usb.c:28: common/usb.c: In function ‘usb_select_config’: common/usb.c:1081:15: error: taking address of packed member of ‘struct usb_device_descriptor’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 1081 | le16_to_cpus(&dev->descriptor.bcdUSB); include/linux/byteorder/big_endian.h:98:38: note: in definition of macro ‘__le16_to_cpus’ 98 | #define __le16_to_cpus(x) __swab16s((x)) | ^ common/usb.c:1081:2: note: in expansion of macro ‘le16_to_cpus’ 1081 | le16_to_cpus(&dev->descriptor.bcdUSB); | ^~~~~~~~~~~~ common/usb.c:1082:15: error: taking address of packed member of ‘struct usb_device_descriptor’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 1082 | le16_to_cpus(&dev->descriptor.idVendor); include/linux/byteorder/big_endian.h:98:38: note: in definition of macro ‘__le16_to_cpus’ 98 | #define __le16_to_cpus(x) __swab16s((x)) | ^ common/usb.c:1082:2: note: in expansion of macro ‘le16_to_cpus’ 1082 | le16_to_cpus(&dev->descriptor.idVendor); | ^~~~~~~~~~~~ common/usb.c:1083:15: error: taking address of packed member of ‘struct usb_device_descriptor’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 1083 | le16_to_cpus(&dev->descriptor.idProduct); include/linux/byteorder/big_endian.h:98:38: note: in definition of macro ‘__le16_to_cpus’ 98 | #define __le16_to_cpus(x) __swab16s((x)) | ^ common/usb.c:1083:2: note: in expansion of macro ‘le16_to_cpus’ 1083 | le16_to_cpus(&dev->descriptor.idProduct); | ^~~~~~~~~~~~ common/usb.c:1084:15: error: taking address of packed member of ‘struct usb_device_descriptor’ may result in an unaligned pointer value [-Werror=address-of-packed-member] 1084 | le16_to_cpus(&dev->descriptor.bcdDevice); include/linux/byteorder/big_endian.h:98:38: note: in definition of macro ‘__le16_to_cpus’ 98 | #define __le16_to_cpus(x) __swab16s((x)) | ^ common/usb.c:1084:2: note: in expansion of macro ‘le16_to_cpus’ 1084 | le16_to_cpus(&dev->descriptor.bcdDevice); | ^~~~~~~~~~~~

Best regards

Heinrich