On Mon, Feb 24, 2020 at 4:20 AM Thomas Backlund <tmb@xxxxxxxxxx> wrote: > > Den 09-01-2020 kl. 17:12, skrev Christian König: > > Hi Christoph, > > > > Am 09.01.20 um 15:14 schrieb Christoph Hellwig: > >> Hi Woody, > >> > >> sorry for the late reply, I've been off to a vacation over the holidays. > >> > >> On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote: > >>> Regression in 5.4 kernel on 32-bit Radeon IBM T40 > >>> triggered by > >>> commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713 > >>> Author: Christoph Hellwig <hch@xxxxxx> > >>> Date: Thu Aug 15 09:27:00 2019 +0200 > >>> > >>> Howdy, > >>> The above patch has triggered a display problem on IBM Thinkpad T40, > >>> where > >>> the screen is covered with a lots of random short black horizontal > >>> lines, > >>> or distorted letters in X terms. > >>> > >>> The culprit seems to be that the dma_get_required_mask() is returning a > >>> value 0x3fffffff > >>> which is smaller than dma_get_mask()0xffffffff.That results in > >>> dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma > >>> instead of 32-bits. > >> Which is the intended behavior assuming your system has 1GB of memory. > >> Does it? > > > > Assuming the system doesn't have the 1GB split up somehow crazy over the > > address space that should indeed work as intended. > > > >> > >>> If I hardcode "1" as the last parameter to ttm_bo_device_init() in > >>> place of > >>> a call to dma_addressing_limited(),the problem goes away. > >> I'll need some help from the drm / radeon / TTM maintainers if there are > >> any other side effects from not passing the need_dma32 paramters. > >> Obviously if the device doesn't have more than 32-bits worth of dram and > >> no DMA offset we can't feed unaddressable memory to the device. > >> Unfortunately I have a very hard time following the implementation of > >> the TTM pool if it does anything else in this case. > > > > The only other thing which comes to mind is using huge pages. Can you > > try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled? > > > > > Any progress on this ? > > We have a bugreport in Mageia with the hw: > Dell Inspiron 5100, 32-bit P4 processor, 2GB of RAM, Radeon Mobility > 7500 (RV200) graphics > > that gets display issues too and reverting the offending commit restores > normal behaviour. > > and the same issue is still there with 5.5 series kernels. Does disabling HIMEM or setting radeon.agpmode=-1 on the kernel command line in grub fix the issue? Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
