New subject: possible regression Radeon RV280 (R3xx/R4xx ?) card freeze, re-apply old patch ?

8 Nov 2013


      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 --------
Betreff: 	Fwd: Fwd: Fwd: Re: regression on RV280 card freeze, patch not 
applicable any more
Datum: 	Fri, 25 Oct 2013 15:04:33 +0200
Von: 	Jochen Rollwagen joro-2013@t-online.de
An: 	xorg-driver-ati@lists.x.org
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 --------
Betreff: 	Fwd: Fwd: Re: regression on RV280 card freeze, patch not 
applicable any more
Datum: 	Fri, 25 Oct 2013 11:31:32 +0200
Von: 	Jochen Rollwagen joro-2013@t-online.de
An: 	xorg-driver-ati@lists.x.org
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=b2145aea36bb035...) 
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@lists.sourceforge.net/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 --------
Betreff: 	Fwd: Re: regression on RV280 card freeze, patch not applicable 
any more
Datum: 	Fri, 18 Oct 2013 15:32:18 +0200
Von: 	Jochen Rollwagen joro-2013@t-online.de
An: 	xorg-driver-ati@lists.x.org
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.