device: 0.775 performance: 0.748 register: 0.699 ppc: 0.669 user-level: 0.654 socket: 0.654 mistranslation: 0.616 peripherals: 0.612 vnc: 0.599 risc-v: 0.586 semantic: 0.548 network: 0.541 graphic: 0.536 permissions: 0.520 VMM: 0.499 i386: 0.497 TCG: 0.488 arm: 0.482 boot: 0.454 x86: 0.440 architecture: 0.431 PID: 0.428 KVM: 0.421 hypervisor: 0.410 debug: 0.408 virtual: 0.392 files: 0.372 kernel: 0.363 assembly: 0.234 UHCI fails to signal stall response When TD execution results in STALL error (STALL handshake, no stall as a result of err count reaching 0), there is no way to know about it except for checking that TD. IMO it is an error condition and it should be reflected in the status register (and issue an interrupt if enabled). Ways to replicate: Send a query that is answered by stall (like set_idle request to a mouse) Expected behavior: UHCI hc sets status bit 1 (usb error interrupt) and issues an interrupt current behavior: Neither status bit is set nor interrupt triggered Version 0.14 attached patch for current master (quick fix, it might be I got something wrong) Hi, Thanks for reporting this issue. Just so you are aware: the qemu USB maintainer is probably going to be away for a while longer, so don't be too worried if this patch doesn't get looked at for 2-4 weeks. Brad No problem, it's not like it breaks something. This fix just makes driver development easier. On Thu, Apr 14, 2011 at 11:35 AM, jvesely