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[174.21.70.228]) by smtp.gmail.com with ESMTPSA id d3sm887207pjk.16.2021.06.14.21.17.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Jun 2021 21:17:52 -0700 (PDT) Subject: Re: [PATCH 1/4] mc146818rtc: Make PF independent of PIE To: Jason Thorpe , qemu-devel@nongnu.org, Paolo Bonzini , "Michael S. Tsirkin" , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= References: <20210613211549.18094-1-thorpej@me.com> <20210613211549.18094-2-thorpej@me.com> From: Richard Henderson Message-ID: <5c2ae675-f734-174d-6640-baebc817f3ba@linaro.org> Date: Mon, 14 Jun 2021 21:17:50 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210613211549.18094-2-thorpej@me.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::62e; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62e.google.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.489, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Cc: paolo and mst On 6/13/21 2:15 PM, Jason Thorpe wrote: > Make the PF flag behave like real hardware by always running the > periodic timer without regard to the setting of the PIE bit, so > that the PF will be set when the period expires even if an interrupt > will not be raised. This behavior is documented on page 16 of the > MC146818A advance information datasheet. > > Signed-off-by: Jason Thorpe > --- > hw/rtc/mc146818rtc.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c > index 4fbafddb22..366b8f13de 100644 > --- a/hw/rtc/mc146818rtc.c > +++ b/hw/rtc/mc146818rtc.c > @@ -155,10 +155,6 @@ static uint32_t rtc_periodic_clock_ticks(RTCState *s) > { > int period_code; > > - if (!(s->cmos_data[RTC_REG_B] & REG_B_PIE)) { > - return 0; > - } This looks correct, but I don't know enough about this device. r~