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Hello there, i *think* i found a regression (card/system freeze in AGP mode) that must have been in the drm code for quite some time (since the switch to kms drivers) and possibly also the potential solution (re-apply an old patch from pre-kms-days). Affected seem to be older cards (actually, very old cards :-) before R600. I mailed this to the ati driver mailing list, but was told that this is a kernel/drm subject now, so i forward the mail interchange to this list. Details below, one has to start reading from the end upwards to get the chronological order, of course. Could somebody give me a hint on how to re-apply the old patch or whether the info i found is valid ? The next step i would take is to insert some diagnostic messages in radeon_vram_location (see below) and build a new kernel. Cheers Jochen -------- Original-Nachricht --------
more info (and possible solution): void radeon_vram_location in radeon_device.c says * Note: GTT start, end, size should be initialized before calling this * function on AGP platform. * * Note: We don't explicitly enforce VRAM start to be aligned on VRAM size, * this shouldn't be a problem as we are using the PCI aperture as a reference. * Otherwise this would be needed for rv280, all r3xx, and all r4xx, but * not IGP. * so does this mean i just have to re-apply the old patch i found ? struct radeon_mc in radeon.h contains aper_base as a member which could be set/aligned to VRAM size using the code snippet below. Cheers Jochen -------- Original-Nachricht --------
I've done some more researching and found the following: - There's another follow-on-patch ("Extend the alignment workaround to post-rv280 chips as well") to the one indicated below (http://cgit.freedesktop.org/~agd5f/xf86-video-ati/commit/?id=b2145aea36bb035bff048366c607b967d70fff49) that applies to not only RV280 but "rv280, all r3xx, and all r4xx, but not IGP". - the piece of code affected seems to be (IMHO) in drivers/gpu/drm/radeon/: The (Radeon ?) Register RADEON_CONFIG_APER_0_BASE is defined in radeon_reg.h but never used in the driver: radeon_reg.h:#define RADEON_CONFIG_APER_0_BASE 0x0100 in r100.c there's static u32 r100_get_accessible_vram(struct radeon_device *rdev) { u32 aper_size; u8 byte; aper_size = RREG32(RADEON_CONFIG_APER_SIZE); /* Set HDP_APER_CNTL only on cards that are known not to be broken, * that is has the 2nd generation multifunction PCI interface */ if (rdev->family == CHIP_RV280 || rdev->family >= CHIP_RV350) { WREG32_P(RADEON_HOST_PATH_CNTL, RADEON_HDP_APER_CNTL, ~RADEON_HDP_APER_CNTL); DRM_INFO("Generation 2 PCI interface, using max accessible memory\n"); return aper_size * 2; } That's the code executed on my machine according to dmesg. Missing (from the original patch, not applicable any more because of driver reorganization) seems to be CARD32 aper0_base = INREG(RADEON_CONFIG_APER_0_BASE); aper0_base &= ~(mem_size - 1); info->mc_fb_location = (aper0_base >> 16); The patch that seems to have removed/overridden this code is: http://www.mail-archive.com/dri-devel@xxxxxxxxxxxxxxxxxxxxx/msg41307.html According to that patch, it was "booted on PCI r100, PCIE rv370, IGP rs400". So IMHO this could be a classical regression for an AGP RV280 card (like mine) and might explain why PCI mode works. this is Additionally corroborated by this post (http://comments.gmane.org/gmane.comp.freedesktop.xorg/5429): * The above doesn't necessarily work. For example, I've seen machines * with 128Mb configured as 2x64Mb apertures. I'm now _always_ setting * RADEON_HOST_PATH_CNTL. OUTREGP (RADEON_HOST_PATH_CNTL, RADEON_HDP_APER_CNTL, ~RADEON_HDP_APER_CNTL); (which was previously done only on some chip families). I _think_ this is not correct on all cards as the apertures may not be configured correctly (and X doesn't set them up neither, if those correspond to the RADEON_CONFIG_APER registers)" Could a Radeon guru confirm this or am i totally lost? Cheers Jochen -------- Original-Nachricht --------
sorry about that. Anyway, i checked drivers/gpu/drm/radeon and drivers/char/agp/uninorth-agp.c and can't seem to find the patch indicated below. Might it have gone missing :-) ? Am 08.10.2013 18:41, schrieb Michel Dänzer: > [ Please always follow up to the mailing list ] > > On Die, 2013-10-08 at 14:53 +0200, Jochen Rollwagen wrote: >> Am 08.10.2013 10:03, schrieb Michel Dänzer: >>> On Sam, 2013-10-05 at 15:13 +0200, Jochen Rollwagen wrote: >>>> I’m running a RV280 based Radeon 9200 card (I know, an ancient card) >>>> in a Mac Mini G4 (powerpc-architecture) with Ubuntu Precise and the >>>> latest 3.4.64-kernel/ati driver and get lockups when trying to run the >>>> card in AGP mode (KMS enabled). The lockups happen when resetting the >>>> card (that’s what I can infer from the oops-screen). >>> It's the other way around: The kernel radeon driver resets the card to >>> try and get it running again after a lockup. >>> >>>> PCI mode works. After researching I found a old bug that was fixed >>>> back in 2006 (https://bugs.freedesktop.org/show_bug.cgi?id=6011) that >>>> looks like the freeze I experience (since PCI mode – which allocates >>>> 64 MB of memory - works and AGP mode which by default allocates 256 MB >>>> doesn’t). The card has 64 mb memory. >>>> >>>> So the first question is, could this be the problem that causes the >>>> lockups ? >>> Not really. The GART and VRAM memory apertures aren't directly related, >>> and the fix for the bug above should still be incorporated in the >>> current radeon KMS code. >>> >>> Does radeon.agpmode=1 or radeon.agpmode=4 work? >>> >> Thank you for your reply. First, none of the agpmodes work, they just >> take more or less time to lockup the card (1 - slowest, 4 fastest). >> Secondly, if you write that the fix "should be incorporated in the >> current code", i'm somewhat lost because it definitely isn't there. > It's in the kernel now. > Well........no. I checked the 3.4.64 kernel sources after my last Mail and the code isn't in the drivers/gpu/drm/radeon sources. But of course i might have overlooked something. |
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