From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chubb Date: Thu, 20 Nov 2003 22:35:27 +0000 Subject: PIIX5 Doesn't work on IA64 (2.6.0-test9) Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hi, The PIIX5 IDE controller on I2000 IA64 boxen using the 460GX chipset will hang on startup if an ordinary harddrive is plugged into it (it seems to workj for the LSI120 and the CDROM drives). This is because the 460GX chipset contains a PCI expanssion bridge that works like the 450NX PXB, and has the same PCI ID (but a later revision). The PIIX driver, to work around interactions between PIIX4 and the 450NX PXB, tries to disable DMA. Unfortunately, the way it tries to disable DMA doesn't work, and the higher layers think that DMA is still on, and so timeout waiting for DMA, and then hang on bootup. A simple workaround is to tighten the check for the buggy chipset, as in the attached patch. However, someone with more time (and who actually *understands* the IDE subsystem) needs to fix the real bug as well. === piix.c 1.20 vs edited ==--- 1.20/drivers/ide/pci/piix.c Wed Oct 22 09:27:24 2003 +++ edited/piix.c Fri Nov 21 09:28:43 2003 @@ -768,8 +768,8 @@ /* Only on the original revision: IDE DMA can hang */ if(rev = 0x00) no_piix_dma = 1; - /* On all revisions PXB bus lock must be disabled for IDE */ - else if(cfg & (1<<14)) + /* On all revisions below 5 PXB bus lock must be disabled for IDE */ + else if(cfg & (1<<14) && rev < 5) no_piix_dma = 2; } if(no_piix_dma)