Date: Thu, 24 Aug 2006 03:56:32 +0400 From: Oleg Bulyzhin <oleg@FreeBSD.org> To: David Christensen <davidch@broadcom.com> Cc: brad@openbsd.org, Gleb Smirnoff <glebius@FreeBSD.org>, net@FreeBSD.org Subject: Re: bge(4) one packet wedge Message-ID: <20060823235632.GA25876@lath.rinet.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>
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On Wed, Aug 23, 2006 at 12:53:49PM -0700, David Christensen wrote: > This "lost interrupt" type of problem is addressed by the use of the > status_tag > field in the status block. (Listed as bge_rsvd0 in the bge_status_block > structure). > Everytime the status block is updated a new tag value is written to the > status block. > When the ISR starts the driver should record the status_tag value. At > the end > of the ISR, the driver should compare the current status_tag value is > the status > block with the value recorded on entry to the ISR. If the values are > the same > then no additional status block updates have occurred so there shouldn't > be > any packets hanging around. If the values are different then additional > packets > or completions are waiting around so the ISR should loop around again. > At the > end of the ISR the driver will write the status_tag value it last > handled to a > mailbox register, letting the hardware know the last status block update > handled. > If necessary the hardware will generate a new interrupt and start the > process over > again. > > This entire process should be included in the Linux driver, I don't see > it being > used in the bge driver (bge_intr()). > > Dave > Could you please answer few questions? 1) I've found status tag is returned in status block even if bit 9 of Misc. Host Control Register is not set, is it ok? 2) Status tag is returned in bits 0-7 of status tag field of status block, as long as i know it should be returned in bits 31-24, is it ok? 3) If i try to return processed tag (at the end of ISR) in Mailbox 0 register: CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, status_tag << 24); it would lead to disabled interrupts. I've thought this should not happen cause in_isr bits (0-23) are cleared. -- Oleg.
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