From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751125AbeEUUOV (ORCPT ); Mon, 21 May 2018 16:14:21 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41194 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbeEUUOU (ORCPT ); Mon, 21 May 2018 16:14:20 -0400 Date: Mon, 21 May 2018 17:14:15 -0300 From: Mauro Carvalho Chehab To: "Gustavo A. R. Silva" Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Devin Heitmueller Subject: Re: [media] duplicate code in media drivers Message-ID: <20180521171415.00c56487@vento.lan> In-Reply-To: <20180521193951.GA16659@embeddedor.com> References: <20180521193951.GA16659@embeddedor.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, 21 May 2018 14:39:51 -0500 "Gustavo A. R. Silva" escreveu: > Hi Mauro, > > I found some duplicate code with the help of Coccinelle and Coverity. Notice that these are not code patches, they only point out the duplicate code in some media drivers: > > diff -u -p drivers/media/pci/bt8xx/dvb-bt8xx.c /tmp/nothing/media/pci/bt8xx/dvb-bt8xx.c > --- drivers/media/pci/bt8xx/dvb-bt8xx.c > +++ /tmp/nothing/media/pci/bt8xx/dvb-bt8xx.c > @@ -389,9 +389,7 @@ static int advbt771_samsung_tdtc9251dh0_ > else if (c->frequency < 600000000) > bs = 0x08; > else if (c->frequency < 730000000) > - bs = 0x08; > else > - bs = 0x08; > > pllbuf[0] = 0x61; > pllbuf[1] = div >> 8; Hmm... I *suspect* that "bs" here controls the frequency range for the tuner. Analog tuners have separate frequency regions that are controlled via a register, into a 4 or 5 bytes I2C sequence. They're all somewhat a clone of an old Philips design. It should be safe to convert the "BS" sequence on something like: if (c->frequency < 173000000) bs = 0x01; else if (c->frequency < 470000000) bs = 0x02; else bs = 0x08; > diff -u -p drivers/media/usb/dvb-usb/dib0700_devices.c /tmp/nothing/media/usb/dvb-usb/dib0700_devices.c > --- drivers/media/usb/dvb-usb/dib0700_devices.c > +++ /tmp/nothing/media/usb/dvb-usb/dib0700_devices.c > @@ -1741,13 +1741,6 @@ static int dib809x_tuner_attach(struct d > struct dib0700_adapter_state *st = adap->priv; > struct i2c_adapter *tun_i2c = st->dib8000_ops.get_i2c_master(adap->fe_adap[0].fe, DIBX000_I2C_INTERFACE_TUNER, 1); > > - if (adap->id == 0) { > - if (dvb_attach(dib0090_register, adap->fe_adap[0].fe, tun_i2c, &dib809x_dib0090_config) == NULL) > - return -ENODEV; > - } else { > - if (dvb_attach(dib0090_register, adap->fe_adap[0].fe, tun_i2c, &dib809x_dib0090_config) == NULL) > - return -ENODEV; > - } I'm almost sure that, on the second if, it should be adap->fe_adap[1].fe. I tried in the past to check this, but didn't got an answer from the one that wrote the code. Maybe we could add a /* FIXME: check if it is fe_adap[1] */ on the second clause. > > st->set_param_save = adap->fe_adap[0].fe->ops.tuner_ops.set_params; > adap->fe_adap[0].fe->ops.tuner_ops.set_params = dib8096_set_param_override; > diff -u -p drivers/media/dvb-frontends/mb86a16.c /tmp/nothing/media/dvb-frontends/mb86a16.c > --- drivers/media/dvb-frontends/mb86a16.c > +++ /tmp/nothing/media/dvb-frontends/mb86a16.c > @@ -1466,9 +1466,7 @@ static int mb86a16_set_fe(struct mb86a16 > wait_t = (1572864 + state->srate / 2) / state->srate; > if (state->srate < 5000) > /* FIXME ! , should be a long wait ! */ > - msleep_interruptible(wait_t); > else > - msleep_interruptible(wait_t); I suspect that the goal here is to point that sleeping for (1572864 + state->srate / 2) / state->srate when srate is low will mean that it will take a lot of time to converge (probably causing timeout at userspace). Basically, if srate is < 5000, the sleep time will be between 314 and 1575364 ms. The worse case scenario - although not realistic, in practice - is to wait up to 26 seconds. This is a very long time! Probably, the right fix here would be to check if wait_t is bigger than a certain amount of time. If so, return an error. I'm not against removing the if, but, if so, better to add a /* FIXME */ block explaining that. That's said, this is an old device. I doubt anyone would fix it. > > if (sync_chk(state, &junk) == 0) { > iq_vt_set(state, 1); > diff -u -p drivers/media/dvb-frontends/au8522_decoder.c /tmp/nothing/media/dvb-frontends/au8522_decoder.c > --- drivers/media/dvb-frontends/au8522_decoder.c > +++ /tmp/nothing/media/dvb-frontends/au8522_decoder.c > @@ -280,14 +280,9 @@ static void setup_decoder_defaults(struc > AU8522_TOREGAAGC_REG0E5H_CVBS); > au8522_writereg(state, AU8522_REG016H, AU8522_REG016H_CVBS); > > - if (is_svideo) { > /* Despite what the table says, for the HVR-950q we still need > to be in CVBS mode for the S-Video input (reason unknown). */ > /* filter_coef_type = 3; */ > - filter_coef_type = 5; > - } else { > - filter_coef_type = 5; > - } Better ask Devin about this (c/c). > > /* Load the Video Decoder Filter Coefficients */ > for (i = 0; i < NUM_FILTER_COEF; i++) { > > > I wonder if some of the cases above were intentionally coded that way or some code needs to be removed. > > Thanks > -- > Gustavo Thanks, Mauro