On Fri, 2006-06-02 at 11:15 +0200, Jens Axboe wrote: > On Fri, Jun 02 2006, zhao, forrest wrote: > > + /* > > + * Disable FIS reception > > + * > > + * AHCI Rev 1.1 Section 10.1.2: > > + * If PxCMD.FRE is set to '1', software should clear it > > + * to '0' and wait at least 500 milliseconds for PxCMD.FR > > + * to return '0' when read. If PxCMD.FR does not clear > > + * '0' correctly, then software may attempt a port reset > > + * of a full HBA reset to recover. > > + */ > > + tmp &= ~(PORT_CMD_FIS_RX); > > + writel(tmp, port_mmio + PORT_CMD); > > + > > + mdelay(500); > > + work = 1000; > > The spec states that you should wait up to 500msec for this condition to > happen, not wait 500msec before looking at it! So please rework this > bit, a half second potentially wasted busy loop is quite nasty. The spec says If PxCMD.FRE is set to '1', software should clear it to '0' and wait *at least* 500 milliseconds for PxCMD.FR to return '0' when read. It's "at least", not "up to". Thanks, Forrest - : send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
