Hi Maxime Ripard, > -----Original Message----- > From: Maxime Ripard <mripard@xxxxxxxxxx> > Sent: Friday, December 15, 2023 10:24 AM > Subject: Re: [PATCH v15 3/5] drm: renesas: Add RZ/G2L DU Support > > On Thu, Dec 14, 2023 at 03:24:17PM +0000, Biju Das wrote: > > Hi Maxime Ripard, > > > > Thanks for the feedback. > > Thanks, that's super helpful. The architecture is thus similar to vc4 > > Some general questions related to bugs we had at some point with vc4: > > * Where is the display list stored? In RAM or in a dedicated SRAM? [1] It is in DDR (RAM). > > * Are the pointer to the current display list latched? > > * Is the display list itself latched? If it's not, what happens when > the display list is changed while the frame is being generated? There is some protocol defined for SW side and HW side for updating display list See [1] 33.4.8.1 Operation flow of VSPD and DU. All the display list operations are manged here[2] [1] https://www.renesas.com/us/en/document/mah/rzg2l-group-rzg2lc-group-users-manual-hardware-0 [2] https://elixir.bootlin.com/linux/v6.7-rc5/source/drivers/media/platform/renesas/vsp1/vsp1_dl.c#L863 Cheers, Biju
