please don't drop linux-scsi ... just because no-one else has asked the question doesn't mean they're not interested in the answer. Having the answer in the list means that search tools can find it. On Thu, 2007-09-20 at 09:20 -0700, Anil K. Ravindranath wrote: > Oh I see. I looked into the scsi_host_alloc(), now I see this.Thanks. By > setting a dma_boundary to 4G, does it mean the kernel(in block) is > ensuring that a DMA segment will not cross this 4G boundary. I mean a > DMA segment will not be split at 4G boundary. Yes, that's exactly what it means. Primarily, as I said, because PCI bridges can't necessarily span non-DAC to DAC in a single DMA transfer. James > With regards, > Anil > > > On Thu, 2007-09-20 at 19:41 -0500, James Bottomley wrote: > > On Thu, 2007-09-20 at 08:08 -0700, Anil K. Ravindranath wrote: > > > Hi, > > > > > > We have not heard any comments or inputs on this patch. > > > > > > With regards, > > > Anil > > > > > > On Sat, 2007-06-30 at 05:45 -0700, Anil K. Ravindranath wrote: > > > > Subject: [PATCH] aic7xxx driver. Restrict DMA to 32bit for 29320LPE > > > > Adaptec SCSI controller > > > > > > > > Contribution: > > > > > > > > Anil Ravindranath <anil_ravindranath@xxxxxxxxxxx> > > > > > > > > Issue: > > > > > > > > Data Bursts that cross from 32- to 64-Bit address space have incorrect > > > > address for 29320LPE. This leads to potential data corruption. > > > > Where do you think you see this happening? The block layer has a > > dma_boundary parameter (basically a mask which it refuses to allow dma > > to cross). By default this is set to 4GB (because a lot of PCI cards > > have difficulty going from non-DAC to DAC). The aic79xx driver does > > nothing to alter this, so you shouldn't be seeing any DMA segments > > crossing the 4GB boundary. > > > > James > > > > - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
