From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v4 1/5] drm/rockchip: fix fb references in async update Date: Tue, 4 Jun 2019 10:34:22 +0200 Message-ID: <20190604103422.63a61f46@collabora.com> References: <20190603165610.24614-1-helen.koike@collabora.com> <20190603165610.24614-2-helen.koike@collabora.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Helen Koike Cc: dri-devel@lists.freedesktop.org, nicholas.kazlauskas@amd.com, andrey.grodzovsky@amd.com, daniel.vetter@ffwll.ch, linux-kernel@vger.kernel.org, Tomasz Figa , David Airlie , Sean Paul , kernel@collabora.com, harry.wentland@amd.com, =?UTF-8?B?U3TDqXBoYW5l?= Marchesin , Sandy Huang , linux-rockchip@lists.infradead.org, Heiko =?UTF-8?B?U3TDvGJuZXI=?= , linux-arm-kernel@lists.infradead.org, Daniel Vetter List-Id: dri-devel@lists.freedesktop.org On Mon, 3 Jun 2019 17:13:34 -0300 Helen Koike wrote: > On 6/3/19 1:56 PM, Helen Koike wrote: > > In the case of async update, modifications are done in place, i.e. in the > > current plane state, so the new_state is prepared and the new_state is > > cleaned up (instead of the old_state, unlike what happens in a > > normal sync update). > > To cleanup the old_fb properly, it needs to be placed in the new_state > > in the end of async_update, so cleanup call will unreference the old_fb > > correctly. > > > > Also, the previous code had a: > > > > plane_state = plane->funcs->atomic_duplicate_state(plane); > > ... > > swap(plane_state, plane->state); > > > > if (plane->state->fb && plane->state->fb != new_state->fb) { > > ... > > } > > > > Which was wrong, as the fb were just assigned to be equal, so this if > > statement nevers evaluates to true. > > > > Another details is that the function drm_crtc_vblank_get() can only be > > called when vop->is_enabled is true, otherwise it has no effect and > > trows a WARN_ON(). > > > > Calling drm_atomic_set_fb_for_plane() (which get a referent of the new > > fb and pus the old fb) is not required, as it is taken care by > > drm_mode_cursor_universal() when calling > > drm_atomic_helper_update_plane(). > > > > Signed-off-by: Helen Koike > > Cc: # v4.20+ > Fixes: 15609559a834 ("drm/rockchip: update cursors asynchronously > through atomic.") One comment for next time you have to add such tags after the fact: please try to keep lines unwrapped, otherwise patchwork only gets what's on the first line.