6.6-stable review patch. If anyone has any objections, please let me know.
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From: Thierry Reding treding@nvidia.com
[ Upstream commit 86bf8cfda6d2a6720fa2e6e676c98f0882c9d3d7 ]
Tegra DRM doesn't support display on Tegra234 and later, so make sure not to remove any existing framebuffers in that case.
v2: - add comments explaining how this situation can come about - clear DRIVER_MODESET and DRIVER_ATOMIC feature bits
Fixes: 6848c291a54f ("drm/aperture: Convert drivers to aperture interfaces") Signed-off-by: Thierry Reding treding@nvidia.com Reviewed-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com Signed-off-by: Robert Foss rfoss@kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20240223150333.1401582-1-thier... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/tegra/drm.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index ff36171c8fb70..373bcd79257e0 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -1242,9 +1242,26 @@ static int host1x_drm_probe(struct host1x_device *dev)
drm_mode_config_reset(drm);
- err = drm_aperture_remove_framebuffers(&tegra_drm_driver); - if (err < 0) - goto hub; + /* + * Only take over from a potential firmware framebuffer if any CRTCs + * have been registered. This must not be a fatal error because there + * are other accelerators that are exposed via this driver. + * + * Another case where this happens is on Tegra234 where the display + * hardware is no longer part of the host1x complex, so this driver + * will not expose any modesetting features. + */ + if (drm->mode_config.num_crtc > 0) { + err = drm_aperture_remove_framebuffers(&tegra_drm_driver); + if (err < 0) + goto hub; + } else { + /* + * Indicate to userspace that this doesn't expose any display + * capabilities. + */ + drm->driver_features &= ~(DRIVER_MODESET | DRIVER_ATOMIC); + }
err = drm_dev_register(drm, 0); if (err < 0)