> -----Original Message----- > From: kishore kadiyala [mailto:kishorek.kadiyala@xxxxxxxxx] > Sent: Thursday, April 01, 2010 1:32 AM > To: Madhusudhan > Cc: Vimal Singh; tony@xxxxxxxxxxx; svenkatr@xxxxxx; linux- > omap@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > jarkko.lavinen@xxxxxxxxx > Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD card's > peformance. > > On Wed, Mar 31, 2010 at 10:07 PM, Madhusudhan <madhu.cr@xxxxxx> wrote: > > > > > >> -----Original Message----- > >> From: kishore kadiyala [mailto:kishorek.kadiyala@xxxxxxxxx] > >> Sent: Wednesday, March 31, 2010 2:03 AM > >> To: Vimal Singh > >> Cc: Madhusudhan; tony@xxxxxxxxxxx; svenkatr@xxxxxx; linux- > >> omap@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > >> jarkko.lavinen@xxxxxxxxx > >> Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD > card's > >> peformance. > >> > >> Sorry for that and here's the Updated one. > >> > >> From: Kishore Kadiyala <kishore.kadiyala@xxxxxx> > >> > >> This patch improves low speeds for SD cards. > >> OMAP-MMC controller's can support maximum bus width of '8'. > >> when bus width is mentioned as "8" in controller data,the SD > >> stack will check whether bus width is "4" and if not it will > >> set bus width to "1" and there by degrading performance. > >> This patch fixes the issue and improves the performance of > >> SD cards. > >> > >> Signed-off-by: Kishore Kadiyala <kishore.kadiyala@xxxxxx> > >> Signed-off-by: Venkatraman S <svenkatr@xxxxxx> > >> Acked-by: Madhusudhan Chikkature <madhu.cr@xxxxxx> > >> > >> --- > >> In V2 : Appended Signed-off by Venkat and Ack by Madhu > >> > >> Here are my experiment numbers, on a Class 6 SDHC card: > >> Read peformance is increased by 220% > >> Write Performance is increased by 52% > >> > >> drivers/mmc/host/omap_hsmmc.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> > >> diff --git a/drivers/mmc/host/omap_hsmmc.c > b/drivers/mmc/host/omap_hsmmc.c > >> index 83f0aff..8c97c22 100644 > >> --- a/drivers/mmc/host/omap_hsmmc.c > >> +++ b/drivers/mmc/host/omap_hsmmc.c > >> @@ -2092,7 +2092,7 @@ static int __init omap_hsmmc_probe(struct > >> MMC_CAP_WAIT_WHILE_BUSY; > >> > >> if (mmc_slot(host).wires >= 8) > >> - mmc->caps |= MMC_CAP_8_BIT_DATA; > >> + mmc->caps |= (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA); > >> else if (mmc_slot(host).wires >= 4) > >> mmc->caps |= MMC_CAP_4_BIT_DATA; > >> > > Kishore, > > > > Since this patch is not yet pushed it makes sense to fix the readability > > issue. > > > > Since 8-bit is the max how about: > > > > if (mmc_slot(host).wires == 8) > > mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA; > > if (mmc_slot(host).wires == 4) > > mmc->caps |= MMC_CAP_4_BIT_DATA; > > > Madhu, > > In the above snippet, it checks whether wires are 8 or 4 and if not > neither set's capability to "1". > Does it make sense to check whether the wires are 8,4,1 and if not > any[8,4,1] throw error and come out. > It is good enough to just check for 8-bit and 4-bit. The 1-bit does not need any explicit check since it is default. Regards, Madhu > Regards, > Kishore > > This would be little easy to read the code. > > > > Can you please repost the patch?? > > > > Regards, > > Madhu > > > >> -- > >> 1.6.3.3 > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
