Hi Philippe, On Thu, Jan 18, 2018 at 11:40:48AM +0000, Philippe CORNU wrote: > On 01/11/2018 12:16 PM, Philippe CORNU wrote: > > To be honest, I do not really like the memcpy here too and I agree with > > you regarding the BE issue. > > > > My first "stm" driver (ie. before using this "freescale/rockchip" > > dw-mipi-dsi driver with the memcpy) used the "exact" same code as the > > Tegra dsi tegra_dsi_writesl() function with the 2 loops. > > > > https://elixir.free-electrons.com/linux/v4.14/source/drivers/gpu/drm/tegra/dsi.c#L1248 > > > > > > IMHO, it is better than memcpy... > > I added these 3 "documentation" lines, maybe we may reuse them or > > something similar... > > > > /* > > * Write 8-bit payload data into the 32-bit payload data register. > > * ex: payload data "0x01, 0x02, 0x03, 0x04, 0x05, 0x06" will become > > * "0x04030201 0x00000605" 32-bit writes > > */ > > > > Not sure it helps to fix the BE issue but we may add a TODO stating that > > "this loop has not been tested on BE"... > > > > What is your opinion? I'm sorry, I don't think I noticed your reply here. I'm trying to unbury some email, but that's sometimes a losing battle... That code actually does look correct, and it's perhaps marginally better-looking in my opinion. It's up to you if you want to propose another patch :) At this point, it's only a matter of nice code, not correctness I believe. > As your patch has been merged, I have few short questions and for each > related new patch, I would like to know if you prefer that I implement > it or if you prefer to do it by yourself, it's really like you want, on > my side, no problem to make them all, some or none, I don't want us to > implement these in parallel :-) > > * Do you have any opinion regarding Tegra-like loops vs the memcpy? (see > my comment above) If you think the Tegra-like loops is a better approach > than memcpy, there is a small patch to write. My opinion is above. > * Returned value with number of bytes received/transferred: there is a > small patch to write I don't think I followed that one very well. I'm not sure my opinion really matters, as long as you get someone else to agree. I do not plan to write any such patch in the near term. > * Regarding read operations: I propose to add a TODO + DRM_WARN in case > someone want to use the API for read operations. Note that I plan to > implement the read feature but I do not know yet when and maybe Rockchip > people already have something ~ready? The warning would be nice to do now, regardless. Rockchip folks wrote up something for read support here [1], but it's based on a semi-forked version of the driver (we're trying to clean up the divergence, but it's not there yet). Perhaps it would provide useful fodder for your work. I don't think Rockchip is immediately working on upstreaming this particular patch, so it's totally fair to handle it yourself. It's got the GPL sign-off ;) Brian [1] https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/863347 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
