Hi > > On Wed, Oct 23, 2019 at 06:25:20AM +0000, S.j. Wang wrote: > > > On Thu, Oct 17, 2019 at 02:21:08PM +0800, Shengjiu Wang wrote: > > > > For P2P output, the output divider should align with the output > > > > sample > > > > > > I think we should avoid "P2P" (or "M2M") keyword in the mainline > > > code as we know M2M will never get merged while somebody working > > > with the mainline and caring about new feature might be confused. > > > > Ok. But we still curious that is there a way to upstream m2m? > > Hmm..I would love to see that happening. Here is an old discussion that > you may want to take a look: > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail > man.alsa-project.org%2Fpipermail%2Falsa-devel%2F2014- > May%2F076797.html&data=02%7C01%7Cshengjiu.wang%40nxp.com%7 > Ce902d2bac4254d2faa0f08d757ecac0e%7C686ea1d3bc2b4c6fa92cd99c5c301 > 635%7C0%7C0%7C637074546320396681&sdata=bg%2BLwRQnUPhW8f > mE972O%2F53MyVftJkK140PSnmC%2FDKQ%3D&reserved=0 > > > > It makes sense to me, yet I feel that the delay at the beginning of > > > the audio playback might be longer as a compromise. I am okay with > > > this decision though... > > > > > > > The maximum divider of asrc clock is 1024, but there is no > > > > judgement for this limitaion in driver, which may cause the > > > > divider setting not correct. > > > > > > > > For non-ideal ratio mode, the clock rate should divide the sample > > > > rate with no remainder, and the quotient should be less than 1024. > > > > > > > > Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx> > > > > > @@ -351,7 +352,9 @@ static int fsl_asrc_config_pair(struct > > > > fsl_asrc_pair > > > *pair) > > > > /* We only have output clock for ideal ratio mode */ > > > > clk = asrc_priv->asrck_clk[clk_index[ideal ? OUT : IN]]; > > > > > > > > - div[IN] = clk_get_rate(clk) / inrate; > > > > + clk_rate = clk_get_rate(clk); > > > > > > The fsl_asrc.c file has config.inclk being set to INCLK_NONE and > > > this sets the "ideal" in this function to true. So, although we tend > > > to not use ideal ratio setting for p2p cases, yet the input clock is > > > still not physically connected, so we still use output clock for div[IN] > calculation? > > > > For p2p case, it can be ideal or non-ideal. For non-ideal, we still > > use Output clock for div calculation. > > > > > > > > I am thinking something simplier: if we decided not to use ideal > > > ratio for "P2P", instead of adding "bool p2p" with the confusing > > > "ideal" in this function, could we just set config.inclk to the same > > > clock as the output one for "P2P"? By doing so, "P2P" won't go > > > through ideal ratio mode while still having a clock rate from the output > clock for div[IN] calculation here. > > > > Bool p2p is to force output rate to be sample rate, no impact to ideal > > Ratio mode. > > I just realized that the function has a bottom part for ideal mode > exclusively -- if we treat p2p as !ideal, those configurations will be missing. > So you're right, should have an extra boolean variable. > > > > > > > > + rem[IN] = do_div(clk_rate, inrate); > > > > + div[IN] = (u32)clk_rate; > > > > if (div[IN] == 0) { > > > > > > Could we check div[IN] and rem[IN] here? Like: > > > if (div[IN] == 0 || div[IN] > 1024) { > > > pair_err(); > > > goto out; > > > } > > > > > > if (!ideal && rem[IN]) { > > > pair_err(); > > > goto out; > > > } > > > > > > According to your commit log, I think the max-1024 limitation should > > > be applied to all cases, not confined to "!ideal" cases right? And > > > we should add some comments also, indicating it is limited by hardware. > > > > For ideal mode, my test result is the divider not impact the output result. > > Which means it is ok for ideal mode even divider is not correct... > > OK. > > > > > > > > pair_err("failed to support input sample rate %dHz > > > > by > > > asrck_%x\n", > > > > inrate, clk_index[ideal ? OUT : > > > > IN]); @@ > > > > -360,11 +363,20 @@ static int fsl_asrc_config_pair(struct > > > > fsl_asrc_pair *pair) > > > > > > > > clk = asrc_priv->asrck_clk[clk_index[OUT]]; > > > > > > > > - /* Use fixed output rate for Ideal Ratio mode (INCLK_NONE) */ > > > > - if (ideal) > > > > - div[OUT] = clk_get_rate(clk) / IDEAL_RATIO_RATE; > > > > - else > > > > - div[OUT] = clk_get_rate(clk) / outrate; > > > > + /* > > > > + * When P2P mode, output rate should align with the out > samplerate. > > > > + * if set too high output rate, there will be lots of Overload. > > > > + * When M2M mode, output rate should also need to align with > > > > + the out > > > > > > For this "should", do you actually mean "M2M could also"? Sorry, I'm > > > just trying to understand everyting here, not intentionally being picky at > words. > > > My understanding is that we still keep the ideal ratio setting > > > because "M2M" still uses it. > > > > We use IDEAL_RATIO_RATE as output rate for m2m mode, it likes a Tricky > > operation, in order to improve the performance. I think The correct > > operation is to use the real output rate, but the performance Is bad. > > So it is a compromise. > > I see. > > > > > > > > + * samplerate, but M2M must use less time to achieve good > > > performance. > > > > + */ > > > > + clk_rate = clk_get_rate(clk); > > > > + if (p2p || !ideal) { > > > > + rem[OUT] = do_div(clk_rate, outrate); > > > > + div[OUT] = clk_rate; > > > > + } else { > > > > + rem[OUT] = do_div(clk_rate, IDEAL_RATIO_RATE); > > > > + div[OUT] = clk_rate; > > > > + } > > > > > > > > if (div[OUT] == 0) { > > > > pair_err("failed to support output sample rate %dHz > > > > by asrck_%x\n", @@ -372,6 +384,16 @@ static int > > > > fsl_asrc_config_pair(struct > > > fsl_asrc_pair *pair) > > > > return -EINVAL; > > > > } > > > > > > > > + if (!ideal && (div[IN] > 1024 || div[OUT] > 1024 || > > > > + rem[IN] != 0 || rem[OUT] != 0)) { > > > > + if (!ideal && (div[IN] > 1024 || div[OUT] > 1024 || rem[IN] > > > > + || rem[OUT] != 0)) { > > > > > > So for ideal == true, these limitaions are not applied any more? > > > Remember that the "ideal" is true for "p2p == true" cases here. > > > > No, not applied. for ideal, the div don't impact the output result > > Even it is not accurate. > > I see. > > > > > > > > + pair_err("The divider can't be used for non ideal mode\n"); > > > > + return -EINVAL; > > > > + } > > > > + > > > > + /* Divider range is [1, 1024] */ > > > > + div[IN] = min_t(u32, 1024, div[IN]); > > > > + div[OUT] = min_t(u32, 1024, div[OUT]); > > > > > > Hmm, this looks like we want to allow ideal ratio cases and p2p > > > cases to operate any way, even if the divider wasn't within the > > > range to get the in/out rates from the output clock? > > > > Yes. We still allow the p2p = true, ideal = false. Note that p2p is > > not Equal to ideal. > > Got it. > > Overall, I feel it's better to have a naming to state the purpose of using > ideal configurations without the IDEAL_RATIO_RATE setup. > bool use_ideal_rate; > And we can put into the asrc_config structure if there's no major problem. > Asrc_config may exposed to user, I don't think user need to care about The using of ideal rate or not. > So the condition check for the calculation would be: > + if (ideal && config->use_ideal_rate) > + rem[OUT] = do_div(clk_rate, IDEAL_RATIO_RATE); > + else > + rem[OUT] = do_div(clk_rate, outrate); > + div[OUT] = clk_rate; > > And for that if (!ideal && div[IN]....rem[OUT]), I feel it would be clear to > have them separately, as the existing "div[IN] == 0" > and "div[OUT] == 0" checks, so that we can tell users which side of the > divider is out of range and what the sample rate and clock rate are. > Do you mean need to combine this judgement with "div[IN] == 0" Or "div[OUT] == 0"? Best regards Wang shengjiu _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
