On 2023-04-14 08:48:43, Abhinav Kumar wrote: > > On 4/14/2023 12:35 AM, Marijn Suijten wrote: > > On 2023-04-12 10:33:15, Abhinav Kumar wrote: > > [..] > >>> What happens if a device boots without DSC panel connected? Will > >>> CTL_DSC_FLUSH be zero and not (unnecessarily, I assume) flush any of the > >>> DSC blocks? Or could this flush uninitialized state to the block? > >>> > >> > >> If we bootup without DSC panel connected, the kernel's cfg->dsc will be > >> 0 and default register value of CTL_DSC_FLUSH will be 0 so it wont flush > >> any DSC blocks. > > > > Ack, that makes sense. However, if I connect a DSC panel, then > > disconnect it (now the register should be non-zero, but cfg->dsc will be > > zero), and then replug a non-DSC panel multiple times, it'll get flushed > > every time because we never clear CTL_DSC_FLUSH after that? > > > > If we remove it after kernel starts, that issue is there even today > without that change because DSI is not a hot-pluggable display so a > teardown wont happen when you plug out the panel. How will cfg->dsc be 0 > then? In that case, its not a valid test as there was no indication to > DRM that display was disconnected so we cannot tear it down. The patch description itself describes hot-pluggable displays, which I believe is the upcoming DSC support for DP? You ask how cfg->dsc can become zero, but this is **exactly** what the patch description describes, and what this patch is removing the `if` for. If we are not allowed to discuss that scenario because it is not currently supported, neither should we allow to apply this patch. With that in mind, can you re-answer the question? - Marijn
