[alsa-devel] [PATCHv3 1/2] ALSA: fix emu8000 DRAM sizing for AWE64 Value

[Takashi Iwai]

At Sun, 11 Jan 2015 16:08:58 -0500,
David Flater wrote:
> 
> Applicable to any kernel since 2013:
> 
> The special case added in commit 1338fc97d07a did not handle the possibility
> that the address space on an AWE64 Value would wrap around at 512 KiB.  That
> is what it does, so the memory is still not detected on those cards.
> 
> Fix that with a logic clean-up that eliminates the need for a special case.
> 
> Signed-off-by: David Flater <dave at flaterco.com>

I have a different "From" address (vger at flaterco.com) from this
sign-off.  Which address should I take?


thanks,

Takashi


> ---
> History:
> 2015-01-11  v3: In response to feedback from Takashi Iwai,
>               Patch 1: Repeat code to avoid goto middle of loop.
>               Patch 2: Use pr_info not printk.
>             Retested on CT4390 (4 MiB) and CT4380 (512 KiB).
> 2015-01-09  v2: In response to feedback from Takashi Iwai,
>                1. Optimize for diff size.
>                  1a. Use goto to avoid indenting and repeating code.
>                  1b. Jettison new debugging printouts.
>                2. Split printk into second patch.
>             Retested on CT4390 (4 MiB) and CT4380 (512 KiB).
> 2015-01-08  v1 patch sent to LKML, Alsa Devel and maintainers.  Tested on
>             unexpanded CT4390 (4 MiB), CT4520 (512 KiB), and CT4380 (512
>             KiB).
> 
>  sound/isa/sb/emu8000.c | 31 +++++++++++++++----------------
>  1 file changed, 15 insertions(+), 16 deletions(-)
> 
> diff --git a/sound/isa/sb/emu8000.c b/sound/isa/sb/emu8000.c
> index 45fcdff..d25e384 100644
> --- a/sound/isa/sb/emu8000.c
> +++ b/sound/isa/sb/emu8000.c
> @@ -378,13 +378,12 @@ init_arrays(struct snd_emu8000 *emu)
>  static void
>  size_dram(struct snd_emu8000 *emu)
>  {
> -	int i, size, detected_size;
> +	int i, size;
>  
>  	if (emu->dram_checked)
>  		return;
>  
>  	size = 0;
> -	detected_size = 0;
>  
>  	/* write out a magic number */
>  	snd_emu8000_dma_chan(emu, 0, EMU8000_RAM_WRITE);
> @@ -392,10 +391,19 @@ size_dram(struct snd_emu8000 *emu)
>  	EMU8000_SMALW_WRITE(emu, EMU8000_DRAM_OFFSET);
>  	EMU8000_SMLD_WRITE(emu, UNIQUE_ID1);
>  	snd_emu8000_init_fm(emu); /* This must really be here and not 2 lines back even */
> +	snd_emu8000_write_wait(emu);
>  
> -	while (size < EMU8000_MAX_DRAM) {
> +	/*
> +	 * Detect first 512 KiB.  If a write succeeds at the beginning of a
> +	 * 512 KiB page we assume that the whole page is there.
> +	 */
> +	EMU8000_SMALR_WRITE(emu, EMU8000_DRAM_OFFSET);
> +	EMU8000_SMLD_READ(emu); /* discard stale data  */
> +	if (EMU8000_SMLD_READ(emu) != UNIQUE_ID1)
> +		goto skip_detect;   /* No RAM */
> +	snd_emu8000_read_wait(emu);
>  
> -		size += 512 * 1024;  /* increment 512kbytes */
> +	for (size = 512 * 1024; size < EMU8000_MAX_DRAM; size += 512 * 1024) {
>  
>  		/* Write a unique data on the test address.
>  		 * if the address is out of range, the data is written on
> @@ -431,18 +439,9 @@ size_dram(struct snd_emu8000 *emu)
>  		snd_emu8000_read_wait(emu);
>  
>  		/* Otherwise, it's valid memory. */
> -		detected_size = size + 512 * 1024;
> -	}
> -
> -	/* Distinguish 512 KiB from 0. */
> -	if (detected_size == 0) {
> -		snd_emu8000_read_wait(emu);
> -		EMU8000_SMALR_WRITE(emu, EMU8000_DRAM_OFFSET);
> -		EMU8000_SMLD_READ(emu); /* discard stale data  */
> -		if (EMU8000_SMLD_READ(emu) == UNIQUE_ID1)
> -			detected_size = 512 * 1024;
>  	}
>  
> +skip_detect:
>  	/* wait until FULL bit in SMAxW register is false */
>  	for (i = 0; i < 10000; i++) {
>  		if ((EMU8000_SMALW_READ(emu) & 0x80000000) == 0)
> @@ -455,9 +454,9 @@ size_dram(struct snd_emu8000 *emu)
>  	snd_emu8000_dma_chan(emu, 1, EMU8000_RAM_CLOSE);
>  
>  	snd_printdd("EMU8000 [0x%lx]: %d Kb on-board memory detected\n",
> -		    emu->port1, detected_size/1024);
> +		    emu->port1, size/1024);
>  
> -	emu->mem_size = detected_size;
> +	emu->mem_size = size;
>  	emu->dram_checked = 1;
>  }
>  
> -- 
> 1.8.4
>