Memory access noise on Clip+

[Gunbuster]

Hi bertrik,

I tried your new build, at startup it say Ver. 4fc4f4e-130712

Sadly I can't hear any improvement with both of my devices.

Thank you for your hard work and please don't hesitate to share new builds if you have other clues about this issue.

[b0hoon]

Hi.

I have a clip+, variant 0 and have no ANY noise with unbranded 2GB card, class 4. Rockbox version is 8723132-120830, so after 3.8. So my guess is that it depends on the hardware (sd card).

[Gunbuster]

Hi b0hoon,

It could be the card yes, as I have already stated I have two memory cards, a Sandisk class 4 and a Trenscend class 10 and I can't hear any difference one from another.

Two different brand, two different speed, the only redundancy is the size (32gb.)

So the size of the card could be one of the root of the problem, I will try to have access on a different card size this weekend to test this theory.

Still it don't explain why two different version of rockbox can sound different with the same hardware (both player and SD card.)

Edit : I just tried with a friend's 16gb class 10 (also Transcend), and still no difference.

[Gunbuster]

So based on the research of bertrik and gevaerts I tried to mess with the sources and make build of rockbox with those patch reverted, and I found the culprit.

* http://git.rockbox.org/?p=rockbox.git;a=commit;h=8351a1aa9db98bab1f66274ee7b7e33839a31c60

What I did is :

Code: [Select]

Launch the VM
git clone git://git.rockbox.org/rockbox ./Desktop/rockbox
cd ./Desktop/rockbox
mkdir build
cd build
../tools/configure
62
patch -p0 -R < 8351a1aa9db98bab1f66274ee7b7e33839a31c60

However when Applied the patch it said :

Code: [Select]

--------------------------
|--- a/apps/plugins/SOURCES
|+++ b/apps/plugins/SOURCES
--------------------------
File to patch: ../apps/plugins/SOURCES
patching file ../apps/plugins/SOURCES
Unreversed patch detected!  Ignore -R? [n] 

So only this patch has been applied

Code: [Select]

--- a/firmware/target/arm/as3525/sd-as3525v2.c
+++ b/firmware/target/arm/as3525/sd-as3525v2.c
@@ -549,40 +549,11 @@ static int sd_init_card(const int drive)
     /*  Card back to full speed  */
     MCI_CLKDIV &= ~(0xFF);    /* CLK_DIV_0 : bits 7:0 = 0x00 */
 
-    if (sd_v2)
-    {
-        /* Attempt to switch cards to HS timings, non HS cards just ignore this */
-        /*  CMD7 w/rca: Select card to put it in TRAN state */
-        if(!send_cmd(drive, SD_SELECT_CARD, card_info[drive].rca, MCI_RESP, &response))
-            return -7;
-
-        if(sd_wait_for_tran_state(drive))
-            return -8;
-
-        /* CMD6 */
-        if(!send_cmd(drive, SD_SWITCH_FUNC, 0x80fffff1, MCI_RESP, &response))
-            return -9;
-
-        /* This delay is a bit of a hack, but seems to fix card detection
-           problems with some SD cards (particularly 16 GB and bigger cards).
-           Preferably we should handle this properly instead of using a delay,
-           see also FS#11870. */
-        sleep(HZ/10);
-
-        /*  We need to go back to STBY state now so we can read csd */
-        /*  CMD7 w/rca=0:  Deselect card to put it in STBY state */
-        if(!send_cmd(drive, SD_DESELECT_CARD, 0, MCI_NO_RESP, NULL))
-            return -10;
-    }
-
     /* CMD9 send CSD */
     if(!send_cmd(drive, SD_SEND_CSD, card_info[drive].rca,
                  MCI_RESP|MCI_LONG_RESP, card_info[drive].csd))
         return -11;
 
-    /* Another delay hack, see FS#11798 */
-    mci_delay();
-
     sd_parse_csd(&card_info[drive]);
 
     if(drive == INTERNAL_AS3525) /* The OF is stored in the first blocks */

Edit : For anyone who want to test the build :
https://www.dropbox.com/s/vn3m816omnfli7e/rockbox.zip

[404_user_not_found]

You should try a new patch http://gerrit.rockbox.org/r/#/c/512/

[Gunbuster]

Thank you 404_user_not_found, we need people to test this as for the moment I'm like the only person in the world who have noted this so I don't expect it to make it to the master branch.

Furthermore it's a very lazy approach as I am no developer, I just reverted some past changes and we need people who know about this like bertrik to investigate further.

All I know is it greatly reduced the noise to a state where it were prior 3.8.1

[[Saint]]

Perhaps my prior post was looked over, or something was lost in translation, but you are far from being the only person in the world to have noted this.

This has been noted a few times, across multiple devices.


[Saint]

[Gunbuster]

Saint, by any mean I didn't overlooked your post, I know you acknowledged the problem exist.

Still for the time being, and to my knowledge, I'm the only one who have noticed an improvement with older firmwares, this is a fact.

This is why it needs further testing from people who suffer from the same issue.

Sorry again for the misunderstanding.

[404_user_not_found]

My steps to reproduce a noticeable memory access noise in rockbox 3.13 with a new revision of sansa clip+ 8gb. This noise is only noticeable at the start of each tracks and noise stops after some seconds of playing.
1) Play big files that requires a high extensive disk activity like wav files with uncompressed PCM codec or FLACs. The tracks should have a some seconds of empty sound at the start. Just set volume to zero.
2) Listen with in-ears headphones with low impedance with low sensitivity (I tested with Koss the plug headphones). I can't notice a memory access noise with other types of headphones.

So may be you can get a rid of noise by changing headphones to another with better quality?

Thank you 404_user_not_found, we need people to test this as for the moment I'm like the only person in the world who have noted this so I don't expect it to make it to the master branch.

With my steps to reproduce a noise this patch and your build changes nothing.

All I know is it greatly reduced the noise to a state where it were prior 3.8.1

can't test with this version because of new revision of my sansa clip+, but noticed that 3.8.1 can't detect my internal memory but detects sd card. So I will try to make some tweaks to run rockbox from sd card.
I successfully run 3.7 in my sansa clip+ from sd card. And with my steps to reproduce a noise nothing changes - I also can notice a same noise as it was in 3.13.

[saratoga]

The audibility of any analog noise will depend on the sensitivity of the headphones. Wither sensitivity the noise must be louder to be heard.

Regarding this issue, listening to the noise is not a great way to test since everyone has different headphones and different opinions. A better way would be to play silence, record the noise and then measure its amplitude.

[db30]

Hello fellow Rockboxers!

I'm also affected by the memory access issue on Clip+, with and without the SD card connected.
The noise is present when the player is booting, on changing tracks and on seeking. During playback it isn't present at all or it's just inaudible.
Some noise can also be heard while the original firmware is used, but it's much less loud than on Rockbox and it's also present for shorter periods of time.

What I've done so far:
- checked on 3.7 - no changes
- checked on 3.13 - no changes
- checked on the build from post #18 - no changes

I see that there's a new patch in post #19, but I simply don't know how to compile it. If someone could put a precompiled version on the forums, I'd test it and submit the results with a great pleasure.

Cheers!

[saratoga]

I'm pretty sure this is just a hardware defect with some Clip+ players, so I don't think any patch is going to help you. 

[mesb]

I'm pretty sure this is just a hardware defect with some Clip+ players, so I don't think any patch is going to help you.

I have the same.
And almost not on sandisk fw.
Maybe there is sense to try any workaround even switchable through menu?

[saratoga]

If you discover a work around I think it makes sense to try it.