On Tue, 26 Apr 2011, Rabin Vincent wrote: > On Wed, Feb 2, 2011 at 21:30, Arnd Bergmann <a...@arndb.de> wrote: > > As noticed by Peter Maydell, the EHCI device driver in Linux gets > > miscompiled by some versions of arm-gcc (still need to find out which) > > due to a combination of problems: > > > > 1. In include/linux/usb/ehci_def.h, struct ehci_caps is defined > > with __attribute__((packed)), for no good reason. This is clearly > > a bug and needs to get fixed, but other drivers have the same bug > > Was a patch submitted for this? I couldn't find it in the archives. > U-Boot seems to be fixing this by adding an "aligned(4)" instead > of removing the packed: > > http://www.mail-archive.com/u-boot@lists.denx.de/msg51418.html
ISTR a patch was submitted, but apparently it never got picked up. > > and it used to work. The attribute forces byte access on all members > > accessed through pointer dereference, which is not allowed on > > MMIO accesses in general. The specific code triggering the problem > > in Peter's case is in ehci-omap.c: > > � � � �omap->ehci->regs = hcd->regs > > � � � � � � � �+ HC_LENGTH(readl(&omap->ehci->caps->hc_capbase)); > > In my case it's this writel() in ehci-hub.c that gets chopped into > strbs: > > /* force reset to complete */ > ehci_writel(ehci, temp & ~(PORT_RWC_BITS | PORT_RESET), > status_reg); Why would that get messed up? The status_reg variable doesn't have any __atribute__((packed)) associated with it. Alan Stern
