From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3C59005A.4080400@elsoft.ch> Date: Thu, 31 Jan 2002 09:29:14 +0100 From: "David =?ISO-8859-1?Q?M=FCller?= (ELSOFT AG)" MIME-Version: 1.0 To: Armin Kuster Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: [PATCH] 3 patches against linuxppc_dev-2.4.18-pre7 References: <3C57F9AC.9040008@elsoft.ch> <3C58410B.802BC1F4@mvista.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Hi Armin Kuster wrote: > "David Müller (ELSOFT AG)" wrote: > >>Hello >> >>The attached patch fixes the following issues: >> >> - arch/ppc/kernel/ppc4xx_pic.c >> fixed constant in ppc405_pic_get_irq() >> (should be NR_AIC_IRQS as in ppc403_pic_get_irq()) >> > > David, > > include/asm-ppc/irq.h > NR_IRQS = (NR_AIC_IRQS + NR_BOARD_IRQS) and was defined to allow > cascading UIC's. > NR_BOARD_IRQS is defined in some of the board files and its default is > in include/asm-ppc/ibm4xx.h > > So i don't see the need to patch that file but the others look fine. > > Exactly, NR_IRQS is the the total number of irqs possible in the system as this number of irqs is reserved in the irq_desc table. For example, we have a system with a PPC405GP and an additional PC like 8259 PIC pair, we have NR_AIC_IRQS (32) + NR_BOARD_IRQS (16) = NR_IRQS (48). In ppc405_pic_get_irq() the following code is executed: irq = 32 - ffs(bits); if (irq == NR_IRQS) irq = -1; return(irq); with NR_IRQS equal 48 the condition is never true ! This results in an endless while-loop in do_IRQ() in arch/ppc/kernel/irq.c Either this or my understanding how things are working is totally wrong. ;-) Additionally, i don't see me why ppc403_pic_get_irq() is using NC_AIC_IRQS while ppc405_pic_get_irq() is using NR_IRQS. Shouldn't they be "symmetric". Dave ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/