Bug 208263

Hello,

unfortunatly I have to report a bug.

Distribution:
gentoo

Hardware:
IBM ThinkPad R40 with a 32bit Pentium-M
RV200/M7 [Mobility Radeon 7500]

Bug report on gentoo:
https://bugs.gentoo.org/717360



I have flickering black lines on X when booting the kernel I compiled from sys-kernel/gentoo-sources-5.4.28 and several following 5.x.x-kernels. No problems with sys-kernel/gentoo-sources-4.19.97.

When the problem persisted I did a bisect. Result is:

commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
Author: Christoph Hellwig <hch@lst.de>
Date:   Thu Aug 15 09:27:00 2019 +0200

    drm/radeon: handle PCIe root ports with addressing limitations
    
    radeon uses a need_dma32 flag to indicate to the drm core that some
    allocations need to be done using GFP_DMA32, but it only checks the
    device addressing capabilities to make that decision.  Unfortunately
    PCIe root ports that have limited addressing exist as well.  Use the
    dma_addressing_limited instead to also take those into account.
    
    Reviewed-by: Christian König <christian.koenig@amd.com>
    Reported-by: Atish Patra <Atish.Patra@wdc.com>
    Signed-off-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

 drivers/gpu/drm/radeon/radeon.h        |  1 -
 drivers/gpu/drm/radeon/radeon_device.c | 12 +++++-------
 drivers/gpu/drm/radeon/radeon_ttm.c    |  2 +-
 3 files changed, 6 insertions(+), 9 deletions(-)


I hope this is relevant and I provide sufficent information! Please let me know if there's more I can provide.