Clamp the fbdev surface size of the available maximumi height to avoid failing to init console emulation. An example error is shown below.
bad framebuffer height 2304, should be >= 768 && <= 768 [drm] Initialized simpledrm 1.0.0 20200625 for simple-framebuffer.0 on minor 0 simple-framebuffer simple-framebuffer.0: [drm] *ERROR* fbdev: Failed to setup generic emulation (ret=-22)
This is especially a problem with drivers that have very small screen sizes and cannot over-allocate at all.
v2: * reduce warning level (Ville)
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: 11e8f5fd223b ("drm: Add simpledrm driver") Reported-by: Amanoel Dawod kernel@amanoeldawod.com Reported-by: Zoltán Kővágó dirty.ice.hu@gmail.com Reported-by: Michael Stapelberg michael+lkml@stapelberg.ch Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Maxime Ripard maxime@cerno.tech Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.14+ --- drivers/gpu/drm/drm_fb_helper.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 6860223f0068..3b5661cf6c2b 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1508,6 +1508,7 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper, { struct drm_client_dev *client = &fb_helper->client; struct drm_device *dev = fb_helper->dev; + struct drm_mode_config *config = &dev->mode_config; int ret = 0; int crtc_count = 0; struct drm_connector_list_iter conn_iter; @@ -1665,6 +1666,11 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper, /* Handle our overallocation */ sizes.surface_height *= drm_fbdev_overalloc; sizes.surface_height /= 100; + if (sizes.surface_height > config->max_height) { + drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n", + config->max_height); + sizes.surface_height = config->max_height; + }
/* push down into drivers */ ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);