Date: Thu, 24 Aug 2006 10:09:22 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: David Christensen <davidch@broadcom.com> Cc: brad@openbsd.org, oleg@FreeBSD.org, net@FreeBSD.org Subject: Re: bge(4) one packet wedge Message-ID: <20060824060922.GF76666@cell.sick.ru> In-Reply-To: <09BFF2FA5EAB4A45B6655E151BBDD90301D43002@NT-IRVA-0750.brcm.ad.broadcom.com> References: <20060823161649.GE76666@cell.sick.ru> <09BFF2FA5EAB4A45B6655E151BBDD90301D43002@NT-IRVA-0750.brcm.ad.broadcom.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Aug 23, 2006 at 12:53:49PM -0700, David Christensen wrote: D> This "lost interrupt" type of problem is addressed by the use of the D> status_tag D> field in the status block. (Listed as bge_rsvd0 in the bge_status_block D> structure). D> Everytime the status block is updated a new tag value is written to the D> status block. D> When the ISR starts the driver should record the status_tag value. At D> the end D> of the ISR, the driver should compare the current status_tag value is D> the status D> block with the value recorded on entry to the ISR. If the values are D> the same D> then no additional status block updates have occurred so there shouldn't D> be D> any packets hanging around. If the values are different then additional D> packets D> or completions are waiting around so the ISR should loop around again. D> At the D> end of the ISR the driver will write the status_tag value it last D> handled to a D> mailbox register, letting the hardware know the last status block update D> handled. D> If necessary the hardware will generate a new interrupt and start the D> process over D> again. D> D> This entire process should be included in the Linux driver, I don't see D> it being D> used in the bge driver (bge_intr()). True, this isn't done in FreeBSD driver. First I started to work on this, but just noticed that I am seeing this problem on 5700 chip, that is known not to support the status tag. What can be the problem for not updated status block in the 5700 case? -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060824060922.GF76666>