There's at least one system that does not interpret the value of the device's 'startadd' field correctly, which leads to incorrectly displayed scanout buffers. Always placing the active scanout buffer at offset 0 works around the problem.

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reported-by: John Donnelly john.p.donnelly@oracle.com Tested-by: John Donnelly john.p.donnelly@oracle.com Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Fixes: 81da87f63a1e ("drm: Replace drm_gem_vram_push_to_system() with kunmap + unpin") Cc: Gerd Hoffmann kraxel@redhat.com Cc: Dave Airlie airlied@redhat.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: David Airlie airlied@linux.ie Cc: Sam Ravnborg sam@ravnborg.org Cc: "Y.C. Chen" yc_chen@aspeedtech.com Cc: Neil Armstrong narmstrong@baylibre.com Cc: Thomas Gleixner tglx@linutronix.de Cc: "José Roberto de Souza" jose.souza@intel.com Cc: Andrzej Pietrasiewicz andrzej.p@collabora.com Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.3+ Link: https://gitlab.freedesktop.org/drm/misc/issues/7 --- drivers/gpu/drm/mgag200/mgag200_drv.c | 36 ++++++++++++++++++++++++++- drivers/gpu/drm/mgag200/mgag200_drv.h | 3 +++ 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c index 397f8b0a9af8..d43951caeea0 100644 --- a/drivers/gpu/drm/mgag200/mgag200_drv.c +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c @@ -30,6 +30,8 @@ module_param_named(modeset, mgag200_modeset, int, 0400); static struct drm_driver driver;

static const struct pci_device_id pciidlist[] = { + { PCI_VENDOR_ID_MATROX, 0x522, PCI_VENDOR_ID_SUN, 0x4852, 0, 0, + G200_SE_A | MGAG200_FLAG_HW_BUG_NO_STARTADD}, { PCI_VENDOR_ID_MATROX, 0x522, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_SE_A }, { PCI_VENDOR_ID_MATROX, 0x524, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_SE_B }, { PCI_VENDOR_ID_MATROX, 0x530, PCI_ANY_ID, PCI_ANY_ID, 0, 0, G200_EV }, @@ -60,6 +62,35 @@ static void mga_pci_remove(struct pci_dev *pdev)

DEFINE_DRM_GEM_FOPS(mgag200_driver_fops);

+static bool mgag200_pin_bo_at_0(const struct mga_device *mdev) +{ + return mdev->flags & MGAG200_FLAG_HW_BUG_NO_STARTADD; +} + +int mgag200_driver_dumb_create(struct drm_file *file, + struct drm_device *dev, + struct drm_mode_create_dumb *args) +{ + struct mga_device *mdev = dev->dev_private; + unsigned long pg_align; + + if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized")) + return -EINVAL; + + pg_align = 0ul; + + /* + * Aligning scanout buffers to the size of the video ram forces + * placement at offset 0. Works around a bug where HW does not + * respect 'startadd' field. + */ + if (mgag200_pin_bo_at_0(mdev)) + pg_align = PFN_UP(mdev->mc.vram_size); + + return drm_gem_vram_fill_create_dumb(file, dev, &dev->vram_mm->bdev, + pg_align, false, args); +} + static struct drm_driver driver = { .driver_features = DRIVER_GEM | DRIVER_MODESET, .load = mgag200_driver_load, @@ -71,7 +102,10 @@ static struct drm_driver driver = { .major = DRIVER_MAJOR, .minor = DRIVER_MINOR, .patchlevel = DRIVER_PATCHLEVEL, - DRM_GEM_VRAM_DRIVER + .debugfs_init = drm_vram_mm_debugfs_init, + .dumb_create = mgag200_driver_dumb_create, + .dumb_map_offset = drm_gem_vram_driver_dumb_mmap_offset, + .gem_prime_mmap = drm_gem_prime_mmap, };

static struct pci_driver mgag200_pci_driver = { diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.h b/drivers/gpu/drm/mgag200/mgag200_drv.h index 4b4f9ce74a84..aa32aad222c2 100644 --- a/drivers/gpu/drm/mgag200/mgag200_drv.h +++ b/drivers/gpu/drm/mgag200/mgag200_drv.h @@ -150,6 +150,9 @@ enum mga_type { G200_EW3, };

+/* HW does not handle 'startadd' field correct. */ +#define MGAG200_FLAG_HW_BUG_NO_STARTADD (1ul << 8) + #define MGAG200_TYPE_MASK (0x000000ff) #define MGAG200_FLAG_MASK (0x00ffff00)