STM32Cube_FW_F2_V1.1.0 question - bug ?

Taylor.Sean · ‎2014-04-22

Posted on April 22, 2014 at 17:40

STM32Cube_FW_F2_V1.1.0\Middlewares\ST\STM32_USB_Host_Library\Core\Src\usbh_core.c

uint8_t USBH_FindInterface(USBH_HandleTypeDef *phost, uint8_t Class, uint8_t SubClass, uint8_t Protocol)

{

USBH_InterfaceDescTypeDef *pif ;

USBH_CfgDescTypeDef *pcfg ;

int8_t if_ix = 0;

pif = (USBH_InterfaceDescTypeDef *)0;

pcfg = &phost->device.CfgDesc;

if((pif->bInterfaceClass == 0xFF) &&(pif->bInterfaceSubClass == 0xFF) && (pif->bInterfaceProtocol == 0xFF))

{

return 0xFF;

}

while (if_ix < USBH_MAX_NUM_INTERFACES)

{

pif = &pcfg->Itf_Desc[if_ix];

Maybe I'm not understanding this, but it looks like the pointer pif is set to address 0 and then is immediately dereferenced in the if statement. I can't see how this can possibly work.

It looks to me like the if((pif->bInterfaceClass == 0xFF) might need to be inside the while() loop, right after pif is assigned the address of one of the interface descriptors.

Montassar BEN ROMDHANE_O · ‎2014-05-29

Posted on May 29, 2014 at 16:40

Hi,

This is a bug; the following statement should be removed:

if((pif->bInterfaceClass == 0xFF) &&(pif->bInterfaceSubClass == 0xFF) && (pif->bInterfaceProtocol == 0xFF))
{
return 0xFF;
}

With regards.