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Wed, 28 Jan 2026 22:29:29 -0800 (PST) Date: Thu, 29 Jan 2026 09:29:26 +0300 From: Dan Carpenter To: ChanSoo Shin , andy@kernel.org Cc: gregkh@linuxfoundation.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-staging@lists.linux.dev Subject: Re: [PATCH v5] fbtft: limit dirty rows based on damage range Message-ID: References: <20260128203938.962414-1-csshin9928@gmail.com> Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260128203938.962414-1-csshin9928@gmail.com> On Thu, Jan 29, 2026 at 05:39:38AM +0900, ChanSoo Shin wrote: > Instead of marking the entire display as dirty, calculate the start > and end rows based on the damage offset and length and only mark the > affected rows dirty. This reduces unnecessary full framebuffer updates > for partial writes. > > Signed-off-by: ChanSoo Shin > --- TL/DR: I suck as a reviewer so I would be nervous to apply this without testing. Andy is an expert here and we trust him so if he's okay with it then great. Or if some other expert could sign off, but I don't know enough to sign off myself. The problem for me is how do I review something like this? Staging is a grab bag of different modules and I'm not an expert in any of the subsystems. Normally, it's easy to review staging patches because they are clean up work which does change how the code works so I just look for unintentional side effects. It's trickier to review a patch like this which changes runtime. If it were fixing a bug, then I could verify the bug is real and say well, "Maybe the fix is wrong, but we were going to corrupt memory anyway, so the worst case is that it is as bad as before. It can't make the problem worse." This is your first kernel patch. You don't work for a company that makes the hardware. You said earlier in a private email that this hasn't been tested. The patch looks reasonable to me, but it also looks simple. If it were that easy why didn't the original author do it? regards, dan carpenter