Hi, On Sunday 08 February 2009, David Fries wrote: > From: David Fries <david@xxxxxxxxx> > > Documentation/kernel-parameters.txt > ide=nodma is no longer valid > > drivers/ide/Kconfig > the module is ide-core.ko not ide > > drivers/ide/ide.c > It took me a while to figure out what the arguments %d.%d:%d to nodma > module parameter ment, so I added a comment to each. This is documented in Documentation/ide/ide.txt however having more documentation won't hurt. > Added a comment to each of the sscanf lines to > There is a bug, if j is 0 it would previously clear all the other bits > except the current device, changed in three different places. > mask &= (1 << i) should be mask &= ~(1 << i) Good catch. > Signed-off-by: David Fries <david@xxxxxxxxx> > Cc: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx> Applied, thanks! > --- > I pretty much wasted my Saturday on this. This is an older VIA > vt82c586b (rev 41) IDE UDMA33 and I've seen disk corruption in the > past with dma enabled, I can't use hdparm because those settings don't > persist across hibernate and restore (that should be another bug > report). ide=nodma was working on the last 2.6.24 kernel, and > kernel-parameters.txt still lists it. I had to go through the change > logs to figure out what happened to ide=nodma, then ide.c to figure > out what replaced it and what %d.%d:%d means (so I documented it so > other would have an easier time), then figure out how to set a module > parameter on the kernel command line when Kconfig said the module name > was ide and ide.nodma=0.0 didn't work, it was ide-core.nodma=0.0. > > Now instead of, > ide=nodma > I have the following. > ide-core.nodma=0.0 ide-core.nodma=0.1 ide-core.nodma=1.0 ide-core.nodma=1.1 The important question is why do you have to use debug "=nodma" option? Is the corruption present in any recent kernels? What disk is it? Do we need to add it to DMA blacklist? I don't recall any reports about such issues and via82cxxx host driver, have you tried to verify that this is not a faulty hardware? > Where else is hdc written 1.0 ? Why doesn't it take ide-core.nodma=hdc ? - simpler code, without parsing of parameters - no dependence on legacy /dev/hd* naming - makes people think harder about reporting/investigating issues instead of covering them up with using debug kernel parameters ;-) [...] > --- a/drivers/ide/ide.c > +++ b/drivers/ide/ide.c > @@ -337,6 +337,7 @@ static int ide_set_dev_param_mask(const char *s, struct kernel_param *kp) > int a, b, i, j = 1; > unsigned int *dev_param_mask = (unsigned int *)kp->arg; > > + /* controller . disk (0 or 1) [ : 1 (set) | 0 (clear) ] */ I did s/disk/device/ here and in other places while merging the patch. Thanks, Bart -- To unsubscribe from this list: 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
