---------- Forwarded message ---------- Date: Mon, 26 Feb 2001 17:19:00 -0500 From: Doug Ledford <[EMAIL PROTECTED]> To: M Sweger <[EMAIL PROTECTED]> Subject: Re: linux 2.2.19pre14 SCSI v5.1.33 patch AIC7895 comments. M Sweger wrote: > > Hello Doug, > > Just to let you know that I've upgraded from linux 2.2.19pre5 > to linux 2.2.19pre14 and here is an updated status. > > 1). My machine is a Dell optiplex 333mhz Intel with a 2940U2W AIC-7895 > chipset and SCSI BIOS v1.33S2 (where S means special Dell stuff) > > 2). This newer patch includes the new scsi driver > v5.1.33/3.2.4 instead of the old one v5.1.31/3.2.4. > > 3). Earlier, I emailed you about a, > "Data overrun in data-in phase, tag 1; > Have seen Data Phase. Length=255, NumSGs=1. > sg[0] - Addr = 0x7fea380 : Length 255" > > error message during bootup for linux kernels 2.2.15-2.2.19pre5. > > 4). HOWEVER, with this newer patch, the "data overrun" error messages > disappear. I've recompiled with TCQ enabled and disabled and with > the TCQ queue size 8 and 24 and no boot problem was encountered. > Moreover, there wasn't any problems running it on UMSDOS with > a Western Digital 9.1 Gig SCSI drive. > > I wonder what changed that eliminated this data overrun problem > in this newer SCSI driver v5.1.33? The Changelog doesn't seem > to hint at a fix in this area. > > Things look good to go. I fixed the WIDE_RESIDUE handler to do the right thing, which fixes the data overrun. Since your drive is operating in wide mode, it transfers two bytes at a time. Since the INQUIRY command that linux sends out is set to a length of 255 bytes, the drive obviously can't send 255 bytes without having an odd tag along byte. It then sends a WIDE_RESIDUE message to the card to let it know that the 256th byte was garbage and ignore it. In the old driver, we didn't handle that message properly and as a result, we thought it was legit and that caused us to signal a data overrun. Now we handle it, we reduce the byte count by 1, and we no longer have an overrun. -- Doug Ledford <[EMAIL PROTECTED]> http://people.redhat.com/dledford Please check my web site for aic7xxx updates/answers before e-mailing me about problems - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
