Janne Grunau
7a7d6681d5
drm_crtc_vblank_get() may fail when it's called before drm_crtc_vblank_on() on a resetted CRTC. This occurs in drm_crtc_helper_funcs' atomic_flush() calls after drm_atomic_helper_crtc_reset() for example directly after probe. Send the vblank event directly in such cases. Avoids following warning in the subsequent drm_crtc_vblank_put() call from the vblank irq handler as below: adp 228200000.display-pipe: [drm] drm_WARN_ON(atomic_read(&vblank->refcount) == 0) WARNING: CPU: 5 PID: 1206 at drivers/gpu/drm/drm_vblank.c:1247 drm_vblank_put+0x158/0x170 ... Call trace: drm_vblank_put+0x158/0x170 (P) drm_crtc_vblank_put+0x24/0x38 adp_fe_irq+0xd8/0xe8 [adpdrm] __handle_irq_event_percpu+0x94/0x318 handle_irq_event+0x54/0xd0 handle_fasteoi_irq+0xa8/0x240 handle_irq_desc+0x3c/0x68 generic_handle_domain_irq+0x24/0x40 Modifying `crtc->state->event` here is fine as crtc->mutex is locked by the non-async atomic commit. In retrospect this looks so obvious that it doesn't warrant a comment in the file. Signed-off-by: Janne Grunau <j@jannau.net> Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io> Link: https://lore.kernel.org/r/20250428-drm_adp_fixes-v2-2-912e081e55d8@jannau.net Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.