A SYNTHVID_RESOLUTION_RESPONSE with resolution_count > 64 walks past the supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT] array in the parse loop. Bound resolution_count against the array size, folded into the existing zero-check.
When the WIN10 resolution probe fails, the caller in hyperv_connect_vsp() left hv->screen_*_max / preferred_* unpopulated, which sets mode_config.max_width / max_height to 0 and makes drm_internal_framebuffer_create() reject every userspace framebuffer with -EINVAL. The pre-WIN10 branch had the same gap for preferred_width / preferred_height. Use a single post-probe fallback guarded by screen_width_max == 0 so both paths converge on the WIN8 defaults. Signed-off-by: Berkant Koc <[email protected]> Assisted-by: Claude:claude-opus-4-7 berkoc-pipeline Fixes: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic video device") Cc: [email protected] # 5.14+ --- drivers/gpu/drm/hyperv/hyperv_drm_proto.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c index 051ecc526..c3d0ff229 100644 --- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c +++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c @@ -391,8 +391,11 @@ static int hyperv_get_supported_resolution(struct hv_device *hdev) return -ETIMEDOUT; } - if (msg->resolution_resp.resolution_count == 0) { - drm_err(dev, "No supported resolutions\n"); + if (msg->resolution_resp.resolution_count == 0 || + msg->resolution_resp.resolution_count > + SYNTHVID_MAX_RESOLUTION_COUNT) { + drm_err(dev, "Invalid resolution count: %d\n", + msg->resolution_resp.resolution_count); return -ENODEV; } @@ -508,9 +511,13 @@ int hyperv_connect_vsp(struct hv_device *hdev) ret = hyperv_get_supported_resolution(hdev); if (ret) drm_err(dev, "Failed to get supported resolution from host, use default\n"); - } else { + } + + if (!hv->screen_width_max) { hv->screen_width_max = SYNTHVID_WIDTH_WIN8; hv->screen_height_max = SYNTHVID_HEIGHT_WIN8; + hv->preferred_width = SYNTHVID_WIDTH_WIN8; + hv->preferred_height = SYNTHVID_HEIGHT_WIN8; } hv->mmio_megabytes = hdev->channel->offermsg.offer.mmio_megabytes; -- 2.47.3
