On 23.05.2018 12:46, Peter Rosin wrote: > On 2018-05-23 11:39, Andrzej Hajda wrote: > > *snip* > >> Panels are managed by dsi host only if dsi host implements it, and it is >> up to dsi host author, it is not mandatory. The only case I am aware of >> is exynos-dsi. I guess most developers are not aware of the problem, or >> they do not care, or ... whatever. This patch shows it very clearly. > *snip* > >> With such approach you do not protect dsi hosts without dynamic panel >> management support. As I said earlier: it is matter of panel consumers >> (for example dsi host), ie if it implements dynamic panel management, it >> should attach panel without creating device_links, as it take care of >> disappearing panels. If it does not perform dynamic management it should >> rely on default behavior - links should be created, to protect drm >> device from using dangling pointers. > So, you're saying that the only place that needs to be patched to call > drm_panel_attach_without_link is exynos_dsi_host_attach()? It should be at least there, but I suppose only there. > > What about the dw-mipi-dsi driver in rockchip/dw-mipi-dsi.c? It also > calls drm_panel_attach/drm_panel_detach in its dw_mipi_dsi_host_attach > and dw_mipi_dsi_host_detach functions. dw_mipi_dsi_host_detach calls only drm_panel_detach, dangling pointer will stay in dsi->panel, and nothing prevents from using it. I guess it is just buggy code. > > Similar thing in bridge/synopsis/dw-mipi-dsi.c, but it calls the > wrappers drm_panel_bridge_add/remove to create an implicit bridge > that in turn handles the panel. So, do we need a to add a > drm_panel_bridge_add_without_link too? Again looks like a buggy code, before panel removal it should be turned off, it should be performed under lock,.... > > What about tegra/dsi.c? It also calls drm_panel_attach in its > tegra_dsi_host_attach function? But that one doesn't detach the > panel in its tegra_dsi_host_detach. Is that a bug? Also looks like a bug, but this is dual-channel device so I am not so sure. Regards Andrzej _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
