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([179.179.238.247]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1831b75ac0fsm36015493c88.15.2026.10.20.05.27.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Oct 2026 05:27:59 -0700 (PDT) From: Vinicius Pedrosa To: ilpo.jarvinen@linux.intel.com Cc: andriy.shevchenko@linux.intel.com, jirislaby@kernel.org, linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev, andre.przywara@arm.com, wens@kernel.org, jernej.skrabec@gmail.com, samuel@sholland.org, enzo.adriano.code@gmail.com Subject: Re: [PATCH v2 2/4] serial: 8250_dw: Only accept a contiguous DLF readback Date: Tue, 20 Oct 2026 09:27:46 -0300 Message-ID: <20261020122746.41699-1-vinicius.eduardo.pedrosa@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <09812a6a-dd0d-9c47-e1ad-5220f1954648@linux.intel.com> References: <09812a6a-dd0d-9c47-e1ad-5220f1954648@linux.intel.com> X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Ilpo, On Tue, 20 Oct 2026, Ilpo Järvinen wrote: > For is_power_of_2(), 0 is not a power of two. And it also wouldn't make > sense to have zero bits in the bit field as it's same as no bit field so > using just is_power_of_2() should be enough. I think the reg != 0 check still needs to stay here, since the test is is_power_of_2(reg + 1), rather than is_power_of_2(reg). For reg == 0, reg + 1 is 1, and is_power_of_2(1) is true. So without the explicit reg check, a zero readback, meaning no DLF, would be accepted as a valid DLF. I'll keep it as: reg && is_power_of_2(reg + 1) in v3. Thanks, Vinicius